Protective effects of selegiline against amyloid beta-induced anxiety-like behavior and memory impairment.

BACKGROUND: Alzheimer's disease (AD) is a complex and common neurodegenerative disorder. The present study aimed to investigate the potential effects of selegiline (SEL) on various aspects of memory performance, anxiety, and oxidative stress in an AD rat model induced by intracerebroventricular injection of amyloid beta1-42 (Aß1-42). METHODS: Oral administration of SEL at a dose of 0.5 mg/kg/day was performed for 30 consecutive days. Following the 30 days, several tests, including the open-field, elevated plus-maze, novel object recognition, Morris water maze, and passive avoidance learning were conducted to assess locomotor activity, anxiety-like behavior, recognition memory, spatial memory, and passive avoidance memory, respectively. RESULTS: The results indicate that the induction of AD in rats led to recognition memory, spatial memory, and passive avoidance memory impairments, as well as increased anxiety. Additionally, the AD rats exhibited a decrease in total antioxidant capacity and an increase in total oxidant status levels, suggesting an imbalance in oxidative-antioxidant status. However, the administration of SEL improved memory performance, reduced anxiety, and modulated oxidative-antioxidant status in AD rats. CONCLUSIONS: These findings provide evidence that SEL may alleviate anxiety-like behavior and cognitive deficits induced by Aß through modulation of oxidative-antioxidant status.

Effects of selegiline on neuronal autophagy involving α-synuclein secretion.

Cell-to-cell transmission of α-synuclein (α-syn) pathology underlies the spread of neurodegeneration in Parkinson's disease. α-Syn secretion is an important factor in the transmission of α-syn pathology. However, it is unclear how α-syn secretion is therapeutically modulated. Here, we investigated effects of monoamine oxidase (MAO)-B inhibitor selegiline on α-syn secretion. Treatment with selegiline promoted α-syn secretion in mouse primary cortical neuron cultures, and this increase was kept under glial cell-eliminated condition by Ara-C. Selegiline-induced α-syn secretion was blocked by cytosolic Ca2+ chelator BAPTA-AM in primary neurons. Selegiline-induced α-syn secretion was retained in MAOA siRNA knockdown, whereas it was abrogated by ATG5 knockdown in SH-SY5Y cells. Selegiline increased LC3-II generation with a reduction in intracellular p62/SQSTM1 levels in primary neurons. The increase in LC3-II generation was blocked by co-treatment with BAPTA-AM in primary neurons. Additionally, fractionation experiments showed that selegiline-induced α-syn secretion occurred in non-extracellular vesicle fractions of primary neurons and SH-SY5Y cells. Collectively, these findings show that selegiline promotes neuronal autophagy involving secretion of non-exosomal α-syn via a change of cytosolic Ca2+ levels.

Chemoenzymatic Synthesis of Selegiline: An Imine Reductase-Catalyzed Approach.

(R)-Homobenzylic amines are key structural motifs present in (R)-selegiline, a drug indicated for the treatment of early-stage Parkinson's disease. Herein, we report a new short chemoenzymatic approach (in 2 steps) towards the synthesis of (R)-selegiline via stereoselective biocatalytic reductive amination as the key step. The imine reductase IR36-M5 mutant showed high conversion (97%) and stereoselectivity (97%) toward the phenylacetone and propargyl amine substrates, offering valuable biocatalysts for synthesizing alkylated homobenzylic amines.

Monoamine oxidase B inhibits epithelial-mesenchymal transition and trigger apoptosis via targeting ERK1/2 signaling pathway in head and neck squamous cell carcinoma.

BACKGROUND: Monoamine oxidase B (MAOB), a flavin monoamine oxidase, regulates biogenic and xenobiotic amine oxidative deaminization. We demonstrate MAOB expression in head and neck epithelium and its biological importance in head and neck squamous cell carcinoma (HNSCC) development. METHODS: First, we found a possible MAOB downregulation in HNSCC using bioinformatic analysis. Second, we validated MAOB expression changes in vitro and assessed its tumorigenicity in HNSCC. Finally, preclinical xenograft models further confirmed our findings. RESULTS: Results proved that MAOB was significantly reduced in HNSCC tissues and cell lines. By comparing MAOB localization in patient specimens, we found that epithelial basal cells express MAOB and that it changes throughout HNSCC development. We observed that MAOB overexpression inhibited HNSCC cell malignancy via lentiviral transfection. We additionally discovered that selegiline partly counter-regulated MAOB overexpression-induced phenotypes in HNSCC cells. CONCLUSIONS: We found that MAOB is a potent biomarker and a unique and essential indication of HNSCC carcinogenesis.

In vitro and in vivo Biological Evaluation of Newly Tacrine-Selegiline Hybrids as Multi-Target Inhibitors of Cholinesterases and Monoamine Oxidases for Alzheimer's Disease.

Purpose: Alzheimer's disease (AD) is the most common neurodegenerative disease, and its multifactorial nature increases the difficulty of medical research. To explore an effective treatment for AD, a series of novel tacrine-selegiline hybrids with ChEs and MAOs inhibitory activities were designed and synthesized as multifunctional drugs. Methods: All designed compounds were evaluated in vitro for their inhibition of cholinesterases (AChE/BuChE) and monoamine oxidases (MAO-A/B) along with their blood-brain barrier permeability. Then, further biological activities of the optimizing compound 7d were determined, including molecular model analysis, in vitro cytotoxicity, acute toxicity studies in vivo, and pharmacokinetic and pharmacodynamic property studies in vivo. Results: Most synthesized compounds demonstrated potent inhibitory activity against ChEs/MAOs. Particularly, compound 7d exhibited good and well-balanced activity against ChEs (hAChE: IC50 = 1.57 µM, hBuChE: IC50 = 0.43 µM) and MAOs (hMAO-A: IC50 = 2.30 µM, hMAO-B: IC50 = 4.75 µM). Molecular modeling analysis demonstrated that 7d could interact simultaneously with both the catalytic active site (CAS) and peripheral anionic site (PAS) of AChE in a mixed-type manner and also exhibits binding affinity towards BuChE and MAO-B. Additionally, 7d displayed excellent permeability of the blood-brain barrier, and under the experimental conditions, it elicited low or no toxicity toward PC12 and BV-2 cells. Furthermore, 7d was not acutely toxic in mice at doses up to 2500 mg/kg and could improve the cognitive function of mice with scopolamine-induced memory impairment. Lastly, 7d possessed well pharmacokinetic characteristics. Conclusion: In light of these results, it is clear that 7d could potentially serve as a promising multi-functional drug for the treatment of AD.

Free-water diffusion magnetic resonance imaging under selegiline treatment in Parkinson's disease.

INTRODUCTION: Monoamine oxidase type B inhibitors, including selegiline, are established as anti-Parkinsonian Drugs. Inhibition of monoamine oxidase type B enzymes might suppress the inflammation because of inhibition to generate reactive oxygen species. However, its effect on brain microstructure remains unclear. The aim of this study is to elucidate white matter and substantia nigra (SN) microstructural differences between Patients with Parkinson's disease with and without selegiline treatment by two independently recruited cohorts. METHODS: Diffusion tensor imaging and free water imaging indices of WM and SN were compared among 22/15 Patients with Parkinson's disease with selegiline (PDselegiline(+)), 33/23 Patients with Parkinson's disease without selegiline (PDselegiline(-)), and 25/20 controls, in the first/second cohorts. Two cohorts were analyzed with different MRI protocols. RESULTS: Diffusion tensor imaging and free-water indices of major white matter tracts were significantly differed between the PDselegiline(-) and controls in both cohorts, although not between the PDselegiline(+) and controls except for restricted areas. Compared with the PDselegiline(+), free-water was significantly higher in the PDselegiline(-) in the inferior fronto-occipital fasciculus, superior longitudinal fasciculus, and superior and posterior corona radiata (first cohort) and the forceps major and splenium of the corpus callosum (second cohort). There were no significant differences in free-water of anterior or posterior substantia nigra between PDselegiline(+) and PDselegiline(-). CONCLUSIONS: Selegiline treatment might reduce the white matter microstructural abnormalities detected by free-water imaging in Parkinson's disease.

Concomitant use of monoamine oxidase inhibitor and tyrosine in parenteral nutrition.

Monoamine oxidase inhibitors (MAOIs) prevent the breakdown of tyramine in the body, and can cause a sudden increase in blood pressure with significant tyramine build up. This phenomenon, when it occurs, is known as tyramine pressor response. It is unknown if tyrosine administered in parenteral nutrition (PN) leads to tyramine build-up with concomitant use of MAOIs. It is also unknown if PN patients who are taking MAOI are at risk for the tyramine pressor response. This is a theoretical possibility as tyrosine endogenously undergoes decarboxylation to produce tyramine. We describe our experience with a 67-year-old woman with severe depression who was on the MAOI, transdermal selegiline. Her clinical course was complicated by an inability to take adequate per oral (PO) intake and she met criteria for unspecified severe protein-calorie-malnutrition in the context of social or environmental circumstances. Therefore, she required PN initiation. PlenamineTM (B. Braun, Bethlehem, PA, USA) was used as the amino acid source in the PN, which contains 39 mg of tyrosine per 100 ml of solution. The patient was monitored closely for any signs of hypertensive crisis while on PN and selegiline. She safely tolerated the combined therapy without any side effects. This is the first documented report of co-administration of PN containing tyrosine along with a MAOI. Our findings suggest that the dose of selegiline used in this patient can be co-administered safely in the setting of PN. However, further study is needed to verify our findings beyond this one patient. In conclusion, we recommend initiating PN and increasing it to goal in patients taking MAOIs, gradually, while monitoring for hypertensive crisis given the theoretical possibility of the tyramine pressor response.

Comparison of the effectiveness, safety, and costs of anti-Parkinson drugs: A multiple-center retrospective study.

AIMS: This study aimed to systematically compare the effectiveness, safety, and costs of different anti-Parkinson drugs (APDs). METHODS: This is a multi-center study that retrospectively analyzed the data of 8420 outpatients with PD from 2014 to 2019 across 30 tertiary hospitals in China. The effectiveness was evaluated by changes in total dosages of APDs, normalized by levodopa equivalent dose (LED) and presented as ΔLEDs; levodopa equivalent dose cost (LEDc) represented the daily cost of APDs; and newly added diagnostics were represented as APDs-related adverse events. RESULTS: A total of 384 patients with eligible medical records for three consecutive years were enrolled. Patients treated with carbidopa/levodopa or levodopa/benserazide had significantly lower mean ΔLEDs than other groups (p < 0.01), followed by pramipexole and selegiline. The piribedil group had the highest ΔLEDs, with mean differences of 112.56-355.04 mg compared to other groups (p < 0.01). Meanwhile, LEDc in the levodopa/benserazide, carbidopa/levodopa, and piribedil groups were significantly lower than those in pramipexole or selegiline groups ($0.088-0.135/day for levodopa/benserazide; $0.070-0.126/day for carbidopa/levodopa; $0.112-0.138/day for piribedil; $0.290-0.332/day for pramipexole; $0.229-0.544/day for selegiline; p < 0.01). Patients with piribedil had more adverse events, with an incidence rate of 35.7%, followed by levodopa/benserazide (25.6%), selegiline (23.5%), carbidopa/levodopa (23.3%), and pramipexole (16.4%). Pramipexole showed a lower incidence rate of adverse events than piribedil, including neuropsychiatric symptoms (p = 0.006), headache/dizziness (p = 0.016), and gastrointestinal symptoms (p = 0.031). CONCLUSIONS: Carbidopa/levodopa or levodopa/benserazide might exhibit better clinical improvement with less medical cost, while piribedil presented less clinical improvement but a higher risk of headache/dizziness, gastrointestinal, and neuropsychiatric symptoms.

Multitracer Approach to Understanding the Complexity of Reactive Astrogliosis in Alzheimer's Brains.

A monoamine oxidase B (MAO-B) selective positron emission tomography (PET) tracer [11C]-deuterium-l-deprenyl holds promise for imaging reactive astrogliosis in neurodegenerative diseases, such as Alzheimer's disease (AD). Two novel PET tracers ([11C]-BU99008 and [18F]-SMBT-1) have recently been developed to assess the complexity of reactive astrogliosis in the AD continuum. We have investigated the binding properties of SMBT-1, l-deprenyl, and BU99008 in AD and cognitively normal control (CN) brains. Competition binding assays with [3H]-l-deprenyl and [3H]-BU99008 versus unlabeled SMBT-1 in postmortem AD and CN temporal and frontal cortex brains demonstrated that SMBT-1 interacted with [3H]-deprenyl at a single binding site (nM range) and with [3H]-BU99008 at multiple binding sites (from nM to µM). Autoradiography studies on large frozen postmortem AD and CN hemisphere brain sections demonstrated that 1 µM SMBT-1 almost completely displaced the [3H]-l-deprenyl binding (>90%), while SMBT-1 only partly displaced the [3H]-BU99008 binding (50-60% displacement) in cortical regions. In conclusion, SMBT-1, l-deprenyl, and BU99008 interact at the same MAO-B binding site, while BU99008 shows an additional independent binding site in AD and CN brains. The high translational power of our studies in human AD and CN brains suggests that the multitracer approach with SMBT-1, l-deprenyl, and BU99008 could be useful for imaging reactive astrogliosis.

Classics in Chemical Neuroscience: Selegiline, Isocarboxazid, Phenelzine, and Tranylcypromine.

The discovery of monoamine oxidase inhibitors (MAOIs) in the 1950s marked a significant breakthrough in medicine, creating a powerful new category of drug: the antidepressant. In the years and decades that followed, MAOIs have been used in the treatment of several pathologies including Parkinson's disease, Alzheimer's disease, and various cancers and as anti-inflammatory agents. Despite once enjoying widespread use, MAOIs have dwindled in popularity due to side effects, food-drug interactions, and the introduction of other antidepressant drug classes such as tricyclic antidepressants (TCAs) and selective serotonin reuptake inhibitors (SSRIs). The recently published prescriber's guide for the use of MAOIs in treating depression has kindled a resurgence of their use in the clinical space. It is therefore timely to review key aspects of the four "classic" MAOIs: high-dose selegiline, isocarboxazid, phenelzine, and tranylcypromine. This review discusses their chemical synthesis, metabolism, pharmacology, adverse effects, and the history and importance of these drugs within the broader field of chemical neuroscience.

Safety comparisons among monoamine oxidase inhibitors against Parkinson's disease using FDA adverse event reporting system.

Monoamine oxidase B (MAO-B) inhibitors are used to control Parkinson's disease (PD). Selegiline, rasagiline, and safinamide are widely used as MAO-B inhibitors worldwide. Although these drugs inhibit MAO-B, there are pharmacological and chemical differences, such as the inhibitory activity, the non-dopaminergic properties in safinamide, and the amphetamine-like structure in selegiline. MAO-B inhibitors may differ in adverse events (AEs). However, differences in actual practical clinics are not fully investigated. A retrospective study was conducted using FAERS, the largest database of spontaneous adverse events. AE signals for MAO-B inhibitors, including selegiline, rasagiline, and safinamide, were detected using the reporting odds ratio method and compared. Hypocomplementemia, hepatic cyst, hepatic function abnormal, liver disorder and cholangitis were detected for selegiline as drug-specific signals. The amphetamine effect was not confirmed for any of the three MAO-B inhibitors. The tyramine reaction was detected as an AE signal only for rasagiline. Moreover, the REM sleep behavior disorder was not detected as an AE signal for safinamide, suggesting that non-dopaminergic effects might be beneficial. Considering the differences in AEs for MAO-B inhibitors will assist with the appropriate PD medication.

The novel design of an intelligent anti-depression transdermal drug delivery system.

Depression is a type of mental disorder with a significant and persistent low mood as the main clinical feature. It is often accompanied by symptoms such as slow thinking, decreased will, loss of appetite, and weight loss. The current treatment methods for depression are mainly medical treatment, psychotherapy, and physical therapy. These treatments are dependent on the patient's autonomy and the patients may suspend treatment due to forgetting or refusing. Therefore, an anti-depressant intelligent drug release system was designed, which can achieve autonomously controlled doses for the treatment of depression by transdermal drug delivery system. The work of this study is as follows: (1) The first module: the electrothermal material heating layer. Several preparation methods were screened, and multiple sets of graphene (GE) electric thermogenic layers were successfully prepared. After increasing the actual energization area to 1 cm × 1 cm, the GE electric thermogenic layer is used as the heating layer of the electrothermal material of the system, and can reach a uniform surface temperature of (45 ± 0.5) °C within 15 s at a voltage of 6 V keeping the temperature fluctuation range not exceeding ±0.03 °C, and the resistance fluctuation range not exceeding ±20 Ω, which plays a role in controlling the temperature and heat treatment of the drug loaded gel layer. (2) The second module: the drug-loaded gel layer. Based on the L16 (45) orthogonal test, the best formulation and process of N-Isopropyl acrylamide-Acrylamide copolymer (P(NIPAAm-co-AAm)) hydrogel was determined. Then, the percutaneous permeability of Selegiline liposome was studied in vitro. (3) A rat model of depression was established using chronic unpredictable mild stress (CUMS) combined with separation. From the aspects of behavior (body weight, sucrose preference test, forced swimming test, open field test) and biochemical indexes (serum proinflammatory cytokines (IL-1ß, TNF-α), hippocampus HE staining observation), the therapeutic effect of hyperthermia, Selegiline oral administration and transdermal administration was discussed.

Striking Neurochemical and Behavioral Differences in the Mode of Action of Selegiline and Rasagiline.

Selegiline and rasagiline are two selective monoamine oxidase B (MAO-B) inhibitors used in the treatment of Parkinson's disease. In their clinical application, however, differences in L-dopa-sparing potencies have been observed. The aim of this study was to find neurochemical and behavioral explanations for the antiparkinsonian effects of these drugs. We found that selegiline possesses a dopaminergic enhancer effect: it stimulated the electrically induced [3H]dopamine release without influencing the resting [3H]dopamine release from rat striatal slices in 10-10-10-9 mol/L concentrations. Rasagiline added in 10-13 to 10-5 mol/L concentrations did not alter the resting or electrically stimulated [3H]dopamine release. Rasagiline (10-9 mol/L), however, suspended the stimulatory effect of selegiline on the electrically induced [3H]dopamine release. The trace amine-associated receptor 1 (TAAR1) antagonist EPPTB (10-8-10-7 mol/L) also inhibited the stimulatory effect of selegiline on [3H]dopamine release. The effect of selegiline in its enhancer dose (5.33 nmol/kg) against tetrabenazine-induced learning deficit measured in a shuttle box apparatus was abolished by a 5.84 nmol/kg dose of rasagiline. The selegiline metabolite (-)methamphetamine (10-9 mol/L) also exhibited enhancer activity on [3H]dopamine release. We have concluded that selegiline acts as an MAO-B inhibitor and a dopaminergic enhancer drug, and the latter relates to an agonist effect on TAAR1. In contrast, rasagiline is devoid of enhancer activity but may act as an antagonist on TAAR1.

PET Evaluation of the Novel F-18 Labeled Reversible Radioligand [18F]GEH200449 for Detection of Monoamine Oxidase-B in the Non-Human Primate Brain.

Positron emission tomography (PET) using radioligands for the enzyme monoamine oxidase B (MAO-B) is increasingly applied as a marker for astrogliosis in neurodegenerative disorders. In the present study, a novel reversible fluorine-18 labeled MAO-B compound, [18F]GEH200449, was evaluated as a PET radioligand in non-human primates. PET studies of [18F]GEH200449 at baseline showed brain exposure (maximum concentration: 3.4-5.2 SUV; n = 5) within the range of that for suitable central nervous system radioligands and a regional distribution consistent with the known localization of MAO-B. Based on the quantitative assessment of [18F]GEH200449 data using the metabolite-corrected arterial plasma concentration as input function, the Logan graphical analysis was selected as the preferred method of quantification. The binding of [18F]GEH200449, as calculated based on regional estimates of the total distribution volume, was markedly inhibited (occupancy >80%) by the administration of the selective MAO-B ligands L-deprenyl (0.5 and 1.0 mg/kg) or rasagiline (0.75 mg/kg) prior to radioligand injection. Radioligand binding was displaceable by the administration of L-deprenyl (0.5 mg/kg) at 25 min after radioligand injection, thus supporting reversible binding to MAO-B. These observations support that [18F]GEH200449 is a reversible MAO-B radioligand suitable for applied studies in humans.

Dihydroxyphenylacetaldehyde Lowering Treatment Improves Locomotor and Neurochemical Abnormalities in the Rat Rotenone Model: Relevance to the Catecholaldehyde Hypothesis for the Pathogenesis of Parkinson's Disease.

The catecholaldehyde hypothesis for the pathogenesis of Parkinson's disease centers on accumulation of 3,4-dihydroxyphenylacetaldehyde (DOPAL) in dopaminergic neurons. To test the hypothesis, it is necessary to reduce DOPAL and assess if this improves locomotor abnormalities. Systemic administration of rotenone to rats reproduces the motor and central neurochemical abnormalities characterizing Parkinson's disease. In this study, we used the monoamine oxidase inhibitor (MAOI) deprenyl to decrease DOPAL production, with or without the antioxidant N-acetylcysteine (NAC). Adult rats received subcutaneous vehicle, rotenone (2 mg/kg/day via a minipump), or rotenone with deprenyl (5 mg/kg/day i.p.) with or without oral NAC (1 mg/kg/day) for 28 days. Motor function tests included measures of open field activity and rearing. Striatal tissue was assayed for contents of dopamine, DOPAL, and other catechols. Compared to vehicle, rotenone reduced locomotor activity (distance, velocity and rearing); increased tissue DOPAL; and decreased dopamine concentrations and inhibited vesicular sequestration of cytoplasmic dopamine and enzymatic breakdown of cytoplasmic DOPAL by aldehyde dehydrogenase (ALDH), as indicated by DA/DOPAL and DOPAC/DOPAL ratios. The addition of deprenyl to rotenone improved all the locomotor indices, increased dopamine and decreased DOPAL contents, and corrected the rotenone-induced vesicular uptake and ALDH abnormalities. The beneficial effects were augmented when NAC was added to deprenyl. Rotenone evokes locomotor and striatal neurochemical abnormalities found in Parkinson's disease, including DOPAL buildup. Administration of an MAOI attenuates these abnormalities, and NAC augments the beneficial effects. The results indicate a pathogenic role of DOPAL in the rotenone model and suggest that treatment with MAOI+NAC might be beneficial for Parkinson's disease treatment.

NLRP3-GABA signaling pathway contributes to the pathogenesis of impulsive-like behaviors and cognitive deficits in aged mice.

BACKGROUND: Perioperative neurocognitive disorders (PND), such as delirium and cognitive impairment, are commonly encountered complications in aged patients. The inhibitory neurotransmitter γ-aminobutyric acid (GABA) is aberrantly synthesized from reactive astrocytes following inflammatory stimulation and is implicated in the pathophysiology of neurodegenerative diseases. Additionally, the activation of NOD-like receptor protein 3 (NLRP3) inflammasome is involved in PND. Herein, we aimed to investigate whether the NLRP3-GABA signaling pathway contributes to the pathogenesis of aging mice's PND. METHODS: 24-month-old C57BL/6 and astrocyte-specific NLRP3 knockout male mice were used to establish a PND model via tibial fracture surgery. The monoamine oxidase-B (MAOB) inhibitor selegiline (1 mg/kg) was intraperitoneally administered once a day for 7 days after the surgery. PND, including impulsive-like behaviors and cognitive impairment, was evaluated by open field test, elevated plus maze, and fear conditioning. Thereafter, pathological changes of neurodegeneration were explored by western blot and immunofluorescence assays. RESULTS: Selegiline administration significantly ameliorated TF-induced impulsive-like behaviors and reduced excessive GABA production in reactive hippocampal astrocytes. Moreover, astrocyte-specific NLRP3 knockout mice reversed TF-induced impulsive-like and cognitive impairment behaviors, decreased GABA levels in reactive astrocytes, ameliorated NLRP3-associated inflammatory responses during the early stage, and restored neuronal degeneration in the hippocampus. CONCLUSIONS: Our findings suggest that anesthesia and surgical procedures trigger neuroinflammation and cognitive deficits, which may be due to NLRP3-GABA activation in the hippocampus of aged mice.

Inhibition of MAOB Ameliorated High-Fat-Diet-Induced Atherosclerosis by Inhibiting Endothelial Dysfunction and Modulating Gut Microbiota.

In this study, monoamine oxidase B (MAOB) was activated under pathological conditions, and was the novel source of cardiovascular reactive oxygen species (ROS). ROS-induced endothelial dysfunction results in sustained and chronic vascular inflammation, which is central to atherosclerotic diseases. However, whether MAOB regulates endothelial oxidative stress and its related mechanism and whether gut microbiota mediates the anti-atherosclerosis effect of MAOB inhibitor remains unclear. In our study, MAOB expressions were elevated in high-fat diet (HFD) fed mice aortas, but only in vascular endothelial cells (not in smooth muscle cells). MAOB small interfering RNA significantly attenuated the palmitic-acid (PA)-induced endothelial oxidative stress and dysfunction. Furthermore, RNA-sequencing data revealed that MAOB knockdown decreased the levels of proinflammatory and apoptotic gene induced by PA. Microarray analysis and qPCR assay showed that miR-3620-5p was significantly decreased under the HFD condition. The dual-luciferase reporter, Western blot and qPCR assay confirmed that miR-3620-5p directly regulated MAOB by binding to its mRNA 3'UTR. Moreover, inhibition of MAOB by selegiline significantly ameliorated endothelial dysfunction and reduced atherosclerotic burden in HFD-fed ApoE-/- mice. Finally, 16S rRNA sequencing showed that selegiline significantly altered the community compositional structure of gut microbiota. Specifically, selegiline treatment enriched the abundance of Faecalibaculum and Akkermansia, decreased the abundance of unclassified_f__Lachnospiraceae, Desulfovibrio, and Blautia, and these genera were significantly correlated with the serum biochemical indices. Taken together, our findings showed that MAOB controlled endothelial oxidative stress homeostasis, and revealed the anti-atherosclerotic effect of selegiline by ameliorating endothelial dysfunction and modulating the composition and function of gut microbiota.

Efficacy and safety of selegiline across different psychiatric disorders: A systematic review and meta-analysis of oral and transdermal formulations.

Selegiline is an irreversible, selective type-B monoamine oxidase inhibitor (MAOI) approved for Parkison's disease-oral and major depressive disorder-transdermal formulation) resulting in non-selective MAOI activity at oral doses≥20 mg/day. The present systematic review and meta-analysis appraises the evidence of different formulations/dosages of selegiline across different psychiatric conditions. We inquired PubMed/MEDLINE/Cochrane-Central/WHO-ICTRP/Clarivate-WebOfScience and the Chinese-Electronic-Journal Database from inception to 10/26/2022 for selegiline trials involving psychiatric patients. Random-effects meta-analyses assessed heterogeneity, publication/risk biases, and confidence in the evidence, followed by sensitivity, subgroup, and meta-regression analyses. Co-primary outcomes were: changes in symptom score (standardized mean difference=SMD) and author-defined response (risk ratios=RRs). RRs of adverse events and all-cause discontinuation were secondary and acceptability outcomes, respectively. Systematic-review included 42 studies; meta-analysis, 23. Selegiline outperformed placebo in depressive symptom reduction (SMD=-0.96, 95%C.I.=-1.78, -0.14, k = 10, n = 1,308), depression (RR=1.61, 95%C.I.=1.20, 2.15, k = 9, n = 1,238) and atypical-depression response (RR=2.23, 95%C.I.=1.35, 3.68, k = 3, n = 136). Selegiline failed to outperform the placebo in negative (k = 4) or positive symptoms of schizophrenia (k = 4), attention-deficit-hyperactivity disorder (ADHD) symptoms reduction (k = 2), and smoking abstinence rate (k = 4). Selegiline did not differ from methylphenidate and ADHD scores (k = 2). No significant difference emerged in acceptability, incident diarrhea, headache, dizziness, and nausea RRs, in contrast to xerostomia (RR=1.58, 95%C.I. =1.03, 2.43, k = 6, n = 1,134), insomnia (RR=1.61, 95%C.I.=1.19, 2.17, k = 10, n = 1,768), and application-site reaction for transdermal formulation (RR=1.81, 95%C.I.=1.40, 2.33, k = 6, n = 1,662). Confidence in findings was low/very-low for most outcomes; moderate for depressive symptoms reduction (transdermal). Selegiline proved effective, safe, and well-tolerated for depressive disorders, yet further evidence is warranted about specific psychiatric disorders.

Selegiline ameliorated dyslipidemia and hepatic steatosis in high-fat diet mice.

Certain monoamine oxidase (MAO) inhibitors exhibit beneficial effects, such as reducing adiposity and metabolic disorders; however, their effects on hepatic lipid metabolism have not been revealed. This study aimed to investigate the effects of a selective MAO-B inhibitor, selegiline, on dyslipidemia and hepatic steatosis in mice induced by a high-fat diet (HFD). Administration of selegiline (0.6 mg/kg body weight) by intraperitoneal injection was found to reduce HFD-induced body weight gain and increases in liver and adiposity coefficients, blood lipids and fatty acid levels. Furthermore, selegiline dramatically reduced the total triglyceride (TG) and cholesterol (TC) levels and lipid accumulation in the livers of HFD-fed mice and palmitic acid (PA)-treated AML-12 hepatocytes. In vivo and in vitro results indicated that selegiline protects against HFD- and PA-induced hepatic inflammation by reducing the expression of proinflammatory cytokines, namely IL-6, TNF-α, IL-1ß, and IL-1α. Additionally, selegiline exhibited antioxidative effects on HFD and PA exposure in mouse liver and AML-12 cells by decreasing the levels of reactive oxygen species (ROS) and malonaldehyde (MDA) and increasing superoxide dismutase (SOD) activity. Further study showed that selegiline administration mitigated the expression of Srebf-1, Fasn, and Acaca and downregulated the expression of Cpt-1 and Pparα in HFD-fed mouse livers and PA-treated AML-12 cells. In conclusion, our findings suggest that selegiline exerts protective effects against HFD-induced dyslipidemia and hepatic steatosis, which may be related to an improved inflammatory response, oxidative stress, and hepatic lipid metabolism.