Quercetin and Its Fermented Extract as a Potential Inhibitor of Bisphenol A-Exposed HT-29 Colon Cancer Cells' Viability.

Bisphenol A (BPA) promotes colon cancer by altering the physiological functions of hormones. Quercetin (Q) can regulate signaling pathways through hormone receptors, inhibiting cancer cells. The antiproliferative effects of Q and its fermented extract (FEQ, obtained by Q gastrointestinal digestion and in vitro colonic fermentation) were analyzed in HT-29 cells exposed to BPA. Polyphenols were quantified in FEQ by HPLC and their antioxidant capacity by DPPH and ORAC. Q and 3,4-dihydroxyphenylacetic acid (DOPAC) were quantified in FEQ. Q and FEQ exhibited antioxidant capacity. Cell viability with Q+BPA and FEQ+BPA was 60% and 50%, respectively; less than 20% of dead cells were associated with the necrosis process (LDH). Treatments with Q and Q+BPA induced cell cycle arrest in the G0/G1 phase, and FEQ and FEQ+BPA in the S phase. Compared with other treatments, Q positively modulated ESR2 and GPR30 genes. Using a gene microarray of the p53 pathway, Q, Q+BPA, FEQ and FEQ+BPA positively modulated genes involved in apoptosis and cell cycle arrest; bisphenol inhibited the expression of pro-apoptotic and cell cycle repressor genes. In silico analyses demonstrated the binding affinity of Q > BPA > DOPAC molecules for ERα and ERß. Further studies are needed to understand the role of disruptors in colon cancer.

[Effect of Sleep Deprivation on the Metabolism of Hippocampal Amino Acids and Monoamine Neurotransmitters in Mice and Their Behaviors]. / ç¡çœ å‰¥å¤ºå¯¹æµ·é©¬åŒºå•èƒºç±»ç¥žç»é€’è´¨ã€æ°¨åŸºé ¸ä»£è°¢åŠå°é¼ è¡Œä¸ºçš„å½±å“.

Objective: To investigate the effect of sleep deprivation on the metabolism of the hippocampal region in mice. Methods: The mice were randomly assigned to three groups, a control group, a 24-h sleep deprivation (SD) group, and a 48-h SD group. Each group had 10 mice. The sleep deprivation model was induced by the modified multiple platform method. The mice's anxiety-like behaviors were assessed with the open field test (OFT) and their depression-like behaviors were assessed with the sucrose preference test (SPT), the forced swimming test (FST), and tail suspension test (TST). High performance liquid chromatography (HPLC) was performed to determine the levels of 6 monoamine neurotransmitters, including 5-hydroxytryptamine (5-HT), norepinephrine (NE), dopamine (DA), gamma-aminobutyric acid (GABA), 5-dihydroxyphenylacetic acid (5-DOPAC), and homovanillic acid (HVA), and 4 amino acids, including glutamic acid (Glu), aspartic acid (Asp), serine (Ser), and taurine (Tau), in the hippocampal region. Immunofluorescence staining was performed to examine the expression of glial cells in the hippocampal region of the mice. The main indicators measured were the levels of monoamine neurotransmitters and amino acids. Results: According to the results of the behavioral analysis, in comparison with the findings for the control group, the 24-h SD mice exhibited increased consumption of sucrose in SFT, significantly decreased total immobility time in FST and TST, and increased total distance covered in OFT, while the 48-h SD mice showed decreased consumption of sucrose in SFT, prolonged total immobility time in FST and TST, and decreased total distance covered in OFT. The results of the HPLC analysis of the monoamine neurotransmitter showed that 24-h SD mice had in their hippocampal region increased levels of DA (P<0.001) and NE (P<0.01) and decreased levels of GABA (P<0.05) in comparison with those of the control mice, while their 5-HT, 5-DOPAC, and HVA levels were not significantly different from those of the control mice. In comparison with those of the control mice, the 48-h SD mice had, in their hippocampal region, decreased levels of 5-HT and NE (all P<0.05), decreased DA (P<0.01), and increased level of GABA (P<0.01), while the levels of 5-DOPAC and HAV were not significantly different. The 48-h SD group showed a significant decrease in the levels of Tau and Glu in comparison with those of the 24-h SD group (all P<0.05). According to the results of immunofluorescence assay, there was no significant difference between the control group and the 24-h SD group in the cell count of glial fibrillary acidic protein (GFAP)-positive cells, while a decline in GFAP-positive cells in comparison with that of the control group was observed in the 48-h SD group. Conclusion: SD of 24 hours may induce anxiety-like behavioral changes in mice by activating their hippocampal glial cells, upregulating the levels of 5-HT, DA, and NE, and increasing the levels of Glu and Tau in the hippocampal region. SD of 48 hours may induce depression-like behavioral changes in mice by inhibiting the activation of glial cells in the hippocampal region and regulating in the opposite direction the levels of the above-mentioned monoamine neurotransmitters and amino acids in the hippocampal region.

The microbiota catabolites of quercetin glycosides concertedly enhance the resistance against acetaldehyde-induced oxidative stress.

3,4-Dihydroxyphenylacetic acid (DOPAC) and 3-hydroxyphenylacetic acid (OPAC) are the predominant catabolites of quercetin glycosides, such as quercetin 4'-O-ß-glucoside from the onion, produced by intestinal microbiota. Although each catabolite has been reported to protect the cells from acetaldehyde-induced cytotoxicity, the effect of their combination remains to be clarified. The purpose of this study was to determine whether the combination of DOPAC and OPAC enhances the resistance against the acetaldehyde-induced oxidative stress in the cultured hepatocytes. The pretreatment of the combination of DOPAC (5 µM) and OPAC (5 µM) showed significant protection against the acetaldehyde- and hydrogen peroxide-induced cytotoxicity, even though each compound at the same concentration did not. This combination also significantly inhibited the intracellular dichlorofluorescin diacetate-detectable reactive oxygen species (ROS) level, whereas the solo treatment did slightly, suggesting that reducing mechanisms of ROS or compounds that enhance ROS production are involved in the cytoprotective effect. The combinatory treatment significantly enhanced the gene expression of not only the aldehyde dehydrogenases (ALDHs), but also glutamate-cysteine ligase, catalytic subunit, the first rate-limiting enzyme of glutathione (GSH) synthesis. Accordingly, both the intracellular GSH level and the total ALDH activity were enhanced by DOPAC plus OPAC. Involvement of GSH in the cytoprotection as well as ALDH up-regulation by the combination was confirmed by the experiments using a GSH biosynthesis inhibitor, buthionine sulfoximine. Taken together, the present results suggested that the quercetin microbiota catabolites concertedly protect the cells from acetaldehyde through a pre-enhanced resistance against oxidative stress by the GSH-dependent up-regulation of ALDHs.

Prenatal SAMe Treatment Induces Changes in Brain Monoamines and in the Expression of Genes Related to Monoamine Metabolism in a Mouse Model of Social Hierarchy and Depression, Probably via an Epigenetic Mechanism.

Reduction in the levels of monoamines, such as serotonin and dopamine in the brain, were reported in patients and animals with depression. SAMe, a universal methyl donor and an epigenetic modulator, is successfully used as an adjunct treatment of depression. We previously found that prenatal treatment with SAMe of Submissive (Sub) mice that serve as a model for depression alleviated many of the behavioral depressive symptoms. In the present study, we treated pregnant Sub mice with 20 mg/kg of SAMe on days 12-15 of gestation and studied the levels of monoamines and the expression of genes related to monoamines metabolism in their prefrontal cortex (PFC) at the age of 3 months. The data were compared to normal saline-treated Sub mice that exhibit depressive-like symptoms. SAMe increased the levels of serotonin in the PFC of female Sub mice but not in males. The levels of 5-HIAA were not changed. SAMe increased the levels of dopamine and of DOPAC in males and females but increased the levels of HVA only in females. The levels of norepinephrine and its metabolite MHPG were unchanged. SAMe treatment changed the expression of several genes involved in the metabolism of these monoamines, also in a sex-related manner. The increase in several monoamines induced by SAMe in the PFC may explain the alleviation of depressive-like symptoms. Moreover, these changes in gene expression more than 3 months after treatment probably reflect the beneficial effects of SAMe as an epigenetic modulator in the treatment of depression.

Anti-Toxoplasma gondii agent isolated from Orostachys malacophylla (Pallas) Fischer.

Botanical medicinal plants have aroused our interest to deal with Toxoplasmosis which can causes serious public health problems. Nipagic acid, gallic acid, ethyl gallate, phloretic acid, protocatechuic acid, methyl p-coumarate, arbutin, and homoprotocatechuic acid are first isolated from Orostachys malacophylla (Pallas) Fischer, their inhibition rate, survival rate, biochemical and viscera index are evaluated using gastric epithelia strain-1(GES-1). Among them, arbutin can effectively prolong the survival time of mice acutely infected with T. gondii, and exhibit the same curative effect as Spiramycin (Spi) group in terms of the glutathione (GSH) and malondialdehyde (MDA) content, alleviate hepatomegaly and splenomegaly. Structure-activity relationship (SAR) and molecular docking implies that phenolic hydroxyl group would be preferred for improvement of activity. In a summary, arbutin is a potential anti-T. gondii candidate for clinical application.

Ecstasy metabolites and monoamine neurotransmitters upshift the Na+/K+ ATPase activity in mouse brain synaptosomes.

3,4-Methylenedioximethamphetamine (MDMA; "ecstasy") is a psychotropic drug with well-known neurotoxic effects mediated by hitherto not fully understood mechanisms. The Na+- and K+-activated adenosine 5'-triphosphatase (Na+/K+ ATPase), by maintaining the ion gradient across the cell membrane, regulates neuronal excitability. Thus, a perturbation of its function strongly impacts cell homeostasis, ultimately leading to neuronal dysfunction and death. Nevertheless, whether MDMA affects the Na+/K+ ATPase remains unknown. In this study, we used synaptosomes obtained from whole mouse brain to test the effects of MDMA, three of its major metabolites [α-methyldopamine, N-methyl-α-methyldopamine and 5-(glutathion-S-yl)-α-methyldopamine], serotonin (5-HT), dopamine, 3,4-dihydroxy-L-phenylalanine (L-Dopa) and 3,4-dihydroxyphenylacetic acid (DOPAC) on the Na+/K+ ATPase function. A concentration-dependent increase of Na+/K+ ATPase activity was observed in synaptosomes exposed to the tested compounds (concentrations ranging from 0.0625 to 200 µM). These effects were independent of protein kinases A and C activities. Nevertheless, a rescue of the compounds' effects was observed in synaptosomes pre-incubated with the antioxidant N-acetylcysteine (1 mM), suggesting a role for reactive species-regulated pathways on the Na+/K+ ATPase effects. In agreement with this hypothesis, a similar increase in the pump activity was found in synaptosomes exposed to the chemical generator of superoxide radicals, phenazine methosulfate (1-250 µM). This study demonstrates the ability of MDMA metabolites, monoamine neurotransmitters, L-Dopa and DOPAC to alter the Na+/K+ ATPase function. This could represent a yet unknown mechanism of action of MDMA and its metabolites in the brain.

[Effect of Rehmanniae Radix on depression-like behavior and hippocampal monoamine neurotransmitters of chronic unpredictable mild stress model rats].

To investigate the effect of Rehmanniae Radix on depression-like behavior and monoamine neurotransmitters of chronic unpredictable mild stress(CUMS) model rats. CUMS combined with isolated feeding was used to induce the depression model of rats. The depression-like behavior of rats was evaluated by sucrose preference test, open field test, and forced swim test. Hematoxylin-Eosin(HE) staining was used to investigate the pathological changes of neurons in the CA1 and CA3 area of hippocampus. Ultra performance liquid chromatography-tandem mass spectrometry(UPLC-MS) was used to detect the contents of 5-hydroxytryptamine(5-HT), 5-hydroxyindoleacetic acid(5-HIAA), dopamine(DA), 3,4-dihydroxyphenylacetic acid(DOPAC), homovanillic acid(HVA), norepinephrine(NE), and 3-methoxy-4-hydroxyphenyl glycol(MHPG) in rats. Western blot was used to detect the protein expressions of tryptophan hydroxylase 2(TPH2), serotonin transporter(SERT), and monoamine oxidase A(MAO-A) in the hippocampus of rats. Compared with the normal group, depressive-like behavior of rats was obvious in the model group. The arrangements of neurons in the CA1 and CA3 area of hippocampus were loose and disorderly. The levels of 5-HT, 5-HIAA, and 5-HT/5-HIAA in the hippocampal area were decreased(P<0.01). The protein expression of TPH2 was decreased(P<0.01), but those of SERT and MAO-A were increased(P<0.01). In the Rehmanniae Radix groups with 1.8 g·kg~(-1) and 7.2 g·kg~(-1), the depression-like behavior of CUMS rats and pathological changes of neurons in CA1, CA3 area of hippocampus were improved. The protein expression of TPH2(P<0.05, P<0.01) was increased, and those of SERT and MAO-A were down-regulated(P<0.05, P<0.01). The levels of 5-HT, 5-HIAA, and 5-HT/5-HIAA in hippocampus were increased(P<0.05, P<0.01). The changes in DA, DOPAC, HVA, DA/(DOPAC +HVA), NE, DHPG, and NE/DHPG were not statistically significant. The results suggested that Rehmanniae Radix improved depression-like behavior of CUMS rats, and the mechanism might be related to the regulation of synthesis, transportation, and metabolism of 5-HT neurotransmitter in the hippocampus.

Sex-Specific Alterations in Dopamine Metabolism in the Brain after Methamphetamine Self-Administration.

Methamphetamine (METH) use disorder affects both sexes, with sex differences occurring in behavioral, structural, and biochemical consequences. The molecular mechanisms underlying these differences are unclear. Herein, we used a rat model to identify potential sex differences in the effects of METH on brain dopaminergic systems. Rats were trained to self-administer METH for 20 days, and a cue-induced drug-seeking test was performed on withdrawal days 3 and 30. Dopamine and its metabolites were measured in the prefrontal cortex (PFC), nucleus accumbens (NAc), dorsal striatum (dSTR), and hippocampus (HIP). Irrespective of conditions, in comparison to females, male rats showed increased 3,4-dihydroxyphenylalanine (DOPA) in the PFC, dSTR, and HIP; increased cys-dopamine in NAc; and increased 3,4-dihydroxyphenylethanol (DOPET) and 3,4-dihydroxyphenylacetic acid (DOPAC) in dSTR. Males also showed METH-associated decreases in DA levels in the HIP but increases in the NAc. Female rats showed METH-associated decreases in DA, DOPAL, and DOPAC levels in the PFC but increases in DOPET and DOPAC levels in the HIP. Both sexes showed METH-associated decreases in NAc DA metabolites. Together, these data document sex differences in METH SA-induced changes in DA metabolism. These observations provide further support for using sex as an essential variable when discussing therapeutic approaches against METH use disorder in humans.

Cranberry Proanthocyanidin and Its Microbial Metabolite 3,4-Dihydroxyphenylacetic Acid, but Not 3-(4-Hydroxyphenyl)-Propionic Acid, Partially Reverse Pro-Inflammatory microRNA Responses in Human Intestinal Epithelial Cells.

SCOPE: The molecular basis underlying the anti-inflammatory and anticarcinogenic properties of cranberries is incompletely understood. The effects of a cranberry proanthocyanidin-rich extract (PAC) and two of its gut microbial metabolites, 3,4-dihydroxyphenylacetic acid (DHPAA) and 3-(4-hydroxyphenyl)-propionic acid (HPPA), on intestinal epithelial cells microRNA (miRNA) expression and their downstream pathways at homeostasis and in inflammatory conditions, are investigated. METHODS AND RESULTS: The expression of 799 miRNAs is quantitatively assessed in differentiated Caco-2BBe1 cells pre-treated with PAC, DHPAA, or HPPA and stimulated with interleukin (IL)-1ß or not. PAC, DHPAA, and HPPA generate subsets of shared and distinct miRNA responses. At homeostasis, miRNAs affected by the metabolites, but not PAC, targeted genes enriched in kinase, Wnt, and growth factor signaling, cell growth and proliferation, apoptosis, and specific cancer pathways. In an inflammatory environment, PAC and DHPAA, but not HPPA, reverses the expression of 16 and two IL-1ß-induced miRNAs, respectively, regulating inflammatory and cancer pathways. CONCLUSION: miRNA modulation is a novel mechanism for PAC bioactivity in the gut. The gut microbiota may be necessary to unlock these effects at homeostasis and partially in inflammation.

Screening of Human Gut Bacterial Culture Collection Identifies Species That Biotransform Quercetin into Metabolites with Anticancer Properties.

We previously demonstrated that flavonoid metabolites inhibit cancer cell proliferation through both CDK-dependent and -independent mechanisms. The existing evidence suggests that gut microbiota is capable of flavonoid biotransformation to generate bioactive metabolites including 2,4,6-trihydroxybenzoic acid (2,4,6-THBA), 3,4-dihydroxybenzoic acid (3,4-DHBA), 3,4,5-trihyroxybenzoic acid (3,4,5-THBA) and 3,4-dihydroxyphenylacetic acid (DOPAC). In this study, we screened 94 human gut bacterial species for their ability to biotransform flavonoid quercetin into different metabolites. We demonstrated that five of these species were able to degrade quercetin including Bacillus glycinifermentans, Flavonifractor plautii, Bacteroides eggerthii, Olsenella scatoligenes and Eubacterium eligens. Additional studies showed that B. glycinifermentans could generate 2,4,6-THBA and 3,4-DHBA from quercetin while F. plautii generates DOPAC. In addition to the differences in the metabolites produced, we also observed that the kinetics of quercetin degradation was different between B. glycinifermentans and F. plautii, suggesting that the pathways of degradation are likely different between these strains. Similar to the antiproliferative effects of 2,4,6-THBA and 3,4-DHBA demonstrated previously, DOPAC also inhibited colony formation ex vivo in the HCT-116 colon cancer cell line. Consistent with this, the bacterial culture supernatant of F. plautii also inhibited colony formation in this cell line. Thus, as F. plautii and B. glycinifermentans generate metabolites possessing antiproliferative activity, we suggest that these strains have the potential to be developed into probiotics to improve human gut health.

In vitro inhibition of glutathione-S-transferase by dopamine and its metabolites, 3,4-dihydroxyphenylacetaldehyde and 3,4-dihydroxyphenylacetic acid.

Parkinson's disease is characterized by dopamine dyshomeostasis and oxidative stress. The aldehyde metabolite of dopamine, 3,4-dihydroxyphenylacetaldehyde (DOPAL), has been reported to be cytotoxic and capable of protein modification. Protein modification by DOPAL has been implicated in the pathogenesis of Parkinson's disease, but the complete pathology is unknown. Our findings show that DOPAL modifies glutathione S-transferase (GST), an important enzyme in the antioxidant defense system. DOPAL, dopamine, and the metabolite 3,4-dihydroxyphenylacetic acid (DOPAC), inhibited the activity of GST isolated from N27 dopaminergic cells at an IC50 of 31.46 µM, 82.32 µM, and 260.0 µM, respectively. DOPAL, dopamine, and DOPAC inhibited commercially available equine liver GST at an IC50 of 23.72 µM, 32.17 µM, and 73.70 µM, respectively. This inhibition was time dependent and irreversible. 1 mM ʟ-cysteine or glutathione fully protected GST activity from DOPAL, DA, and DOPAC inhibition. 1 mM carnosine partially protected GST activity from DA inhibition. Furthermore, ʟ-cysteine was found to protect GST by forming a putative thiazolidine conjugate with DOPAL. We conclude that GST inactivation may be a part of the broader etiopathology of Parkinson's disease.

Structural Features and Toxicity of α-Synuclein Oligomers Grown in the Presence of DOPAC.

The interplay between α-synuclein and dopamine derivatives is associated with oxidative stress-dependent neurodegeneration in Parkinson's disease (PD). The formation in the dopaminergic neurons of intraneuronal inclusions containing aggregates of α-synuclein is a typical hallmark of PD. Even though the biochemical events underlying the aberrant aggregation of α-synuclein are not completely understood, strong evidence correlates this process with the levels of dopamine metabolites. In vitro, 3,4-dihydroxyphenylacetaldehyde (DOPAL) and the other two metabolites, 3,4-dihydroxyphenylacetic acid (DOPAC) and 3,4-dihydroxyphenylethanol (DOPET), share the property to inhibit the growth of mature amyloid fibrils of α-synuclein. Although this effect occurs with the formation of differently toxic products, the molecular basis of this inhibition is still unclear. Here, we provide information on the effect of DOPAC on the aggregation properties of α-synuclein and its ability to interact with membranes. DOPAC inhibits α-synuclein aggregation, stabilizing monomer and inducing the formation of dimers and trimers. DOPAC-induced oligomers did not undergo conformational transition in the presence of membranes, and penetrated the cell, where they triggered autophagic processes. Cellular assays showed that DOPAC reduced cytotoxicity and ROS production induced by α-synuclein aggregates. Our findings show that the early radicals resulting from DOPAC autoxidation produced covalent modifications of the protein, which were not by themselves a primary cause of either fibrillation or membrane binding inhibition. These findings are discussed in the light of the potential mechanism of DOPAC protection against the toxicity of α-synuclein aggregates to better understand protein and catecholamine biology and to eventually suggest a scaffold that can help in the design of candidate molecules able to interfere in α-synuclein aggregation.

Parkinson-like early autonomic dysfunction induced by vagal application of DOPAL in rats.

AIM: To understand why autonomic failures, a common non-motor symptom of Parkinson's disease (PD), occur earlier than typical motor disorders. METHODS: Vagal application of DOPAL (3,4-dihydroxyphenylacetaldehyde) to simulate PD-like autonomic dysfunction and understand the connection between PD and cardiovascular dysfunction. Molecular and morphological approaches were employed to test the time-dependent alternation of α-synuclein aggregation and the ultrastructure changes in the heart and nodose (NG)/nucleus tractus solitarius (NTS). RESULTS: Blood pressure (BP) and baroreflex sensitivity of DOPAL-treated rats were significantly reduced accompanied with a time-dependent change in orthostatic BP, consistent with altered echocardiography and cardiomyocyte mitochondrial ultrastructure. Notably, time-dependent and collaborated changes in Mon-/Tri-α-synuclein were paralleled with morphological alternation in the NG and NTS. CONCLUSION: These all demonstrate that early autonomic dysfunction mediated by vagal application of DOPAL highly suggests the plausible etiology of PD initiated from peripheral, rather than central site. It will provide a scientific basis for the prevention and early diagnosis of PD.

Pharmacological Characterization of 4-Methylthioamphetamine Derivatives.

Amphetamine derivatives have been used in a wide variety of pathologies because of their pharmacological properties as psychostimulants, entactogens, anorectics, and antidepressants. However, adverse cardiovascular effects (sympathomimetics) and substance abuse problems (psychotropic and hallucinogenic effects) have limited their use. 4-Methylthioamphetamine (MTA) is an amphetamine derivative that has shown to inhibit monoamine uptake and monoamine oxidase. However, the pharmacological characterization (neurochemical, behavioral, and safety) of its derivatives 4-ethylthioamphetamine (ETA) and 4-methylthio-phenil-2-butanamine (MT-But) have not been studied. In the current experiments, we show that ETA and MT-But do not increase locomotor activity and conditioned place preference with respect to MTA. At the neurochemical level, ETA and MT-But do not increase in vivo DA release in striatum, but ETA and MT-But affect the nucleus accumbens bioaccumulation of DA and DOPAC. Regarding cardiovascular effects, the administration of MTA and ETA increased the mean arterial pressure and only ETA significantly increases the heart rate. Our results show that the pharmacological and safety profiles of MTA are modulated by changing the methyl-thio group or the methyl group of the aminoethyl chain.

The Microbiota-Derived Metabolite of Quercetin, 3,4-Dihydroxyphenylacetic Acid Prevents Malignant Transformation and Mitochondrial Dysfunction Induced by Hemin in Colon Cancer and Normal Colon Epithelia Cell Lines.

Meat diet plays a pivotal role in colorectal cancer (CRC). Hemin, a metabolite of myoglobin, produced after meat intake, has been involved in CRC initiation. The compound, 3,4-dihydroxyphenylacetic acid (3,4HPAA) is a scarcely studied microbiota-derived metabolite of the flavonoid quercetin (QUE), which exert antioxidant properties. The aim of this study was to determine the protective effect of 3,4HPAA against malignant transformation (increased cell proliferation, decreased apoptosis, DNA oxidative damage and augmented reactive oxidative species (ROS) levels) and mitochondrial dysfunction induced by hemin in normal colon epithelial cells and colon cancer cells. The effect of 3,4HPAA was assessed in comparison to its precursor, QUE and to a known CRC protective agent, sulforaphane (SFN). The results showed that both, tumor and normal cells, exposed to hemin, presented increased cell proliferation, decreased caspase 3 activity and cytochrome c release, as well as augmented production of intracellular and mitochondrial ROS. In addition, hemin decreased the mitochondrial membrane potential (MMP) and the activity of complexes I and II of the electron transport chain. These effects of hemin were prevented by the action of 3,4HPAA. The metabolite showed to be more active than QUE and slightly less active than SFN. In conclusion, 3,4HPAA administration could represent a promising strategy for preventing malignant transformation and mitochondrial dysfunction in colon epithelia induced by hemin.

ß-Methylphenylalanine exerts neuroprotective effects in a Parkinson's disease model by protecting against tyrosine hydroxylase depletion.

We evaluated the neuroprotective effects of ß-methylphenylalanine in an experimental model of rotenone-induced Parkinson's disease (PD) in SH-SY5Y cells and rats. Cells were pre-treated with rotenone (2.5 µg/mL) for 24 hours followed by ß-methylphenylalanine (1, 10 and 100 mg/L) for 72 hours. Cell viability, reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP), mitochondrial fragmentation, apoptosis, and mRNA and protein levels of tyrosine hydroxylase were determined. In a rat model of PD, dopamine (DA) and 3,4-dihydroxyphenylacetic acid (DOPAC) levels, bradykinesia and tyrosine hydroxylase expression were determined. In rotenone-pre-treated cells, ß-methylphenylalanine significantly increased cell viability and MMP, whereas ROS levels, apoptosis and fragmented mitochondria were reduced. ß-Methylphenylalanine significantly increased the mRNA and protein levels of tyrosine hydroxylase in SH-SY5Y cells. In the rotenone-induced rat model of PD, oral administration of ß-methylphenylalanine recovered DA and DOPAC levels and bradykinesia. ß-Methylphenylalanine significantly increased the protein expression of tyrosine hydroxylase in the striatum and substantia nigra of rats. In addition, in silico molecular docking confirmed binding between tyrosine hydroxylase and ß-methylphenylalanine. Our experimental results show neuroprotective effects of ß-methylphenylalanine via the recovery of mitochondrial damage and protection against the depletion of tyrosine hydroxylase. We propose that ß-methylphenylalanine may be useful in the treatment of PD.

1-Methyl-1,2,3,4-tetrahydroisoquinoline - The toxicological research on an exo/endogenous amine with antidepressant-like activity - In vivo, in vitro and in silico studies.

BACKGROUND: 1-Methyl-1,2,3,4-tetrahydroisoquinoline (1MeTIQ) demonstrates significant neuroprotective activity. It can interact with agonistic conformation of dopamine (DA) receptors. 1MeTIQ inhibits the formation of 3,4-dihydroxyphenylacetic acid as well as production of free radicals and shifts DA catabolism toward COMT-dependent O-methylation. 1MeTIQ inhibits both MAO-A and B enzymes activity and increases neurotransmitters levels in the brain. It shows significant antidepressant-like effect in forced swim test (FST) in rats. This compound might be effective for depression therapy in a clinical setting but its success is determined not only by good efficacy, but also by an acceptable its ADMET profile. The use of combination in silico prediction with in vivoand in vitro studies greatly simplifies the search for new, safer and effectively acting drugs. METHODS: The aim of this study was to investigate the degree of histopathological changes in different rats tissues after acute and chronic administration of 1MeTIQ. Additionally, prediction of its properties in terms of absorption, distribution, metabolism, elimination and toxicity in the human body was performed. RESULTS: The obtained data did not show extensive and significant toxic effects of tested substance in in vivo and in vitro studies in rats, and in silico ADMET prediction. CONCLUSIONS: These results can help to discover a new effective and safe antidepressant substance and have important significance in the treatment of depression in clinic. Additionally, the use in the treatment of depression substance with neuroprotective, antioxidant and antidepressant-like effects in the CNS and existing endogenously might be also beneficial in controlling the adverse CNS inflammatory processes accompanying depression.

Role of Parkinson's Disease-Linked Mutations and N-Terminal Acetylation on the Oligomerization of α-Synuclein Induced by 3,4-Dihydroxyphenylacetaldehyde.

Identifying the mechanisms by which the presynaptic protein α-synuclein (aSyn) is associated with neurodegeneration of dopamine neurons is a major priority in the Parkinson's disease (PD) field. Studies indicate that DOPAL (3,4-dihydroxyphenylacetaldehyde), an aldehyde generated from the enzymatic oxidation of dopamine, may convert aSyn monomer into a neurotoxin via formation of covalently stabilized toxic oligomers. Herein we investigated the role of N-terminal acetylation and familial aSyn mutations (A30P, A53T, E46K, G51D, and H50Q) on DOPAL-induced oligomerization of the protein. Our results indicate that the wild-type (WT) N-terminally acetylated aSyn (Ac-aSyn) is less prone to form oligomers upon incubation with DOPAL than the non-N-terminally acetylated protein. On the other hand, familial mutants from Ac-aSyn, particularly A53T, E46K, and H50Q increased the formation of DOPAL-derived aSyn oligomers, especially large oligomers. Binding of aSyn to synaptic-like small unilamellar vesicles (SUVs) protected distinctive aSyn variants against the effects of DOPAL. While N-terminal acetylation increased the protective action of SUVs against DOPAL-induced aSyn oligomerization, A53T, A30P, and H50Q mutations in Ac-aSyn had an opposite effect. This means that PD-linked mutations may not only perturb the affinity of aSyn for membranes but also influence the formation of DOPAL-mediated oligomers. Overall, our findings provide important evidence for the existence of a connection between familial mutations of aSyn, their distinct affinity to lipid membranes, and the formation of potentially toxic oligomers of the protein mediated by DOPAL.

Pharmacokinetic, Antiproliferative and Apoptotic Effects of Phenolic Acids in Human Colon Adenocarcinoma Cells Using In Vitro and In Silico Approaches.

Colon cancer is the second most common cause of cancer deaths in the USA and Europe. Despite aggressive therapies, many tumors are resistant to current treatment protocols and epidemiological data suggest that diet is a major factor in the etiology of colon cancer. This study aimed to evaluate the antioxidant activity and the influence of 3,4-dihydroxyphenylacetic (3,4-DHPAA), p-coumaric (p-CoA), vanillic (VA) and ferulic (FA) acids on cell viability, cell cycle progression, and rate of apoptosis in human colon adenocarcinoma cells (HT-29). The results showed that all compounds tested reduce cell viability in human colon cancer cells. 3,4-DHPAA promoted the highest effect antiproliferative with an increase in the percentage of cells in G0/G1 phase, accompanied by a reduction of cells in G2/M phase. Cell cycle analysis of VA and FA showed a decrease in the proportion of cells in G0/G1 phase (10.0 µM and 100.0 µM). p-CoA and FA acids increased the percentage of apoptotic cells and non-apoptotic cells. 3,4-DHPAA seems to be the substance with the greatest potential for in vivo studies, opening thus a series of perspectives on the use of these compounds in the prevention and treatment of colon cancer.

Exploring the role of methionine residues on the oligomerization and neurotoxic properties of DOPAL-modified α-synuclein.

The dopamine metabolite 3,4-dihydroxyphenylacetaldehyde (DOPAL) is believed to play a central role in Parkinson's disease neurodegeneration by stabilizing potentially toxic oligomers of the presynaptic protein α-Synuclein (aSyn). Besides the formation of covalent DOPAL-Lys adducts, DOPAL promotes the oxidation of Met residues of aSyn, which is also a common oxidative post-translational modification found in the protein in vivo. Herein we set out to address the role of Met residues on the oligomerization and neurotoxic properties of DOPAL-modified aSyn. Our data indicate that DOPAL promotes the formation of two distinct types of aSyn oligomers: large and small (dimer and trimers) oligomers, which seem to be generated by independent mechanisms and cannot be interconverted by using denaturing agents. Interestingly, H2O2-treated aSyn monomer, which exhibits all-four Met residues oxidized to Met-sulfoxide, exhibited a reduced ability to form large oligomers upon treatment with DOPAL, with no effect on the population of small oligomers. In this context, triple Met-Val mutant M5V/M116V/M127V exhibited an increased population of large aSyn-DOPAL oligomers in comparison with the wild-type protein. Interestingly, the stabilization of large rather than small oligomers seems to be associated with an enhanced toxicity of DOPAL-aSyn adducts. Collectively, these findings indicate that Met residues may play an important role in modulating both the oligomerization and the neurotoxic properties of DOPAL-derived aSyn species.