Monoamine oxidase genes polymorphisms and mood disorder

We investigated a genetic association between mood disorders (bipolar and unipolar) and the alleles of monoamine oxidase (MAO) A and B (MAOA and MAOB). One hundred and twelve unrelated Japanese patients (60 bipolar, 52 unipolar) and 100 controls were genotyped for three markers of MAOA and for one marker of MAOB. No statistically significant difference in the distribution of the alleles existed between cases and controls. Therefore, our results did not support the involvement of the alleles at MAOA and MAOB in the etiology of mood disorder. Am. J. Med. Genet. 74:494–496, 1997. © 1997 Wiley-Liss, Inc.     

Monoamine oxidase, tribulin, isatin: basic and applied medical aspects

Monoamine oxidase (MAO) catalyzes the biological degradation of the neurotransmitters monoamines. The altered substrate specificity of MAO may be of pathogenic importance in some cases and MAO inhibitors showed a therapeutical effect in the experimental setting. Analyzing the efficacy of various compounds in inhibiting MAO A and B revealed new approaches to designing new-generation MAO inhibitors. Tribulin is a fraction of endogenous MAO inhibitors that are present in human and animal tissues and biological fluids. Isatin is an endogenous indole which was initially derived from a tribulin fraction. An investigation of the biological properties of tribulin revealed its heterogeneity and some chemical components were identified. It was shown that deficiency of tribulin components that selectively inhibited MAO A long with a larger number of molecules of this enzyme might be of great importance for the development of alcoholism. In addition to MAO inhibition, the physiological concentrations of isatin inhibited the receptor-binding of atrial natriuretic peptides and ANP-stimulated guanylate cyclase (GC). The sensitivity of ANP-GC to isatin might be allosterically regulated. Selective antagonists of natriuretic peptide receptors were found among isatin analogues which may be an effective pharmacological tool for further studies of the role of natriuretic peptides in the body.     

Monoamine and diamine oxidase activities in atopic eczema

Increased plasma histamine levels were associated with significantly lowered diamine and type B monoamine oxidase activities in platelet rich plasma of atopic eczema patients.     

Monoamine oxidase activity in chick cerebral microvessels

In chick brain microvessels, monoamine oxidase activity using catecholamines (dopamine and noradrenaline) and indoleamines (serotonin and tryptamine) as substrates was higher than that measured in synaptosomes and free mitochondria. In contrast, phenylalkyamines such as tyramine and 2-phenylethylamine were more deaminated in free mitochondria and synaptosomes than in microvessels. These results suggest that the activity of monoamine oxidase towards neurotransmitter amines in microvessels should be considered as a site of inactivation of these neurotransmitters in the chick brain parenchyma.     

Monoamine oxidase inhibitors for IgA nephropathy.

IgA nephropathy (IgAN), characterized by renal mesangial deposits of antibodies (of the IgA subtype), is the most common glomerulonephritis worldwide. The cause of IgAN is not known. IgAN can often lead to end stage renal disease (ESRD), and there is no known treatment proven to prevent ESRD in IgAN. Long term use of steroids or other immunosuppressant drugs carry severe toxicities and other risks. IgAN patients have high serum levels of tumor necrosis factor-alpha (TNF). Increased monoamine levels, via increased cellular cyclic AMP, can decrease TNF elaboration. Monoamine oxidase inhibitors (MAO-Is) have been found effective in case studies for a number of diseases, e.g. rheumatoid arthritis and Crohn's disease, characterized by high TNF levels. Here I suggest that MAO-Is might be of utility in IgAN by decreasing TNF levels.     

Monoamine oxidase activity, lipid peroxidation, and morphological changes in human hypothalamus during aging

Progressive gliosis of the hypothalamus during aging in humans is accompanied by activation of monoamine oxidase B activity, intensification of lipid peroxidation, and inhibition of SDH. Density of capillaries decreases. The role of monoamine oxidase B in the induction of lipid peroxidation is discussed.     

Monoamine oxidase: associations with alcohol dependence, smoking and other measures of psychopathology

BACKGROUND: Many reports have appeared on associations between platelet monoamine oxidase (MAO) activity and susceptibility to psychiatric conditions; principally alcohol dependence but also conduct disorder, other drug use and depression. Recently, it has become apparent that MAO activity is inhibited by some component of cigarette smoke, and smokers have low platelet MAO activity. Since the prevalence of smoking is higher in many of the conditions in which MAO has been implicated, the MAO susceptibility associations may be partly, or entirely, false. METHODS: We have measured platelet MAO in 1551 subjects, recruited from the Australian NHMRC Twin Registry, who have provided information on alcohol use and dependence, smoking, conduct disorder, depression, attempted suicide, panic disorder and social phobia. RESULTS: Current smoking reduced platelet MAO activity in a significant and dose-related manner, with no evidence of lower MAO in ex-smokers or in non-smoking subjects with co-twins who smoked. Alcohol use and lifetime DSM-III-R alcohol dependence history were not associated with MAO activity when smoking was taken into account. Depression, panic disorder and social phobia showed no significant associations with platelet MAO activity. Subjects with a history of serious attempts at suicide had low platelet MAO activity; but although the difference from controls was as great as the reduction associated with smoking it was not significant after correction for smoking effects. CONCLUSIONS: Although synaptic MAO activity undoubtedly plays a role in psychopathology, the concept that platelet MAO activity is a direct genetic marker of vulnerability to alcohol dependence cannot be sustained.     

Monoamine oxidase A is highly expressed in classical Hodgkin lymphoma

Monoamine oxidase A (MAOA) is a mitochondrial enzyme that catalyzes oxidative deamination of neurotransmitters and dietary amines and produces H₂O₂. It facilitates the progression of gliomas and prostate cancer, but its expression and functional relevance have not been studied in lymphoma. Here, we evaluated MAOA in 427 cases of Hodgkin and non‐Hodgkin lymphoma and in a spectrum of reactive lymphoid tissues by immunohistochemistry on formalin‐fixed, paraffin‐embedded specimens. MAOA was expressed by Hodgkin Reed–Sternberg (HRS) cells in the majority of classical Hodgkin lymphomas (cHLs) (181/241; 75%), with 34.8% showing strong expression. Weak MAOA was also noted in a minority of primary mediastinal large B‐cell lymphomas (8/47; 17%) and in a mediastinal gray‐zone lymphoma. In contrast, no MAOA was found in non‐neoplastic lymphoid tissues, nodular lymphocyte‐predominant Hodgkin lymphoma (NLPHL; 0/8) or any other non‐Hodgkin lymphomas studied (0/123). MAOA was more common in Epstein–Barr virus (EBV)‐negative compared to EBV‐positive cHL (p < 0.0001) and was especially prevalent in the EBV‐negative nodular sclerosing subtype. Similar to primary human lymphoma specimens, most cHL‐derived cell lines displayed MAOA activity, whereas non‐Hodgkin‐lymphoma‐derived cell lines did not. The MAOA inhibitor clorgyline reduced the growth of L1236 cells and U‐HO1 cells, and shRNA knockdown of MAOA reduced the growth of L1236 cells. Conversely, ectopic overexpression of MAOA increased the growth of MAOA‐negative HDLM2 cells. Combined treatment with clorgyline and ABVD (doxorubicin, bleomycin, vinblastine, dacarbazine) was more effective in reducing cell growth than either regimen alone. In summary, MAOA is highly expressed in cHL and may reflect the distinct biology of this lymphoma. Further studies on the potential utility of MAOA as a diagnostic marker and therapeutic target are warranted. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.     

Monoamine oxidase a gene is associated with borderline personality disorder

OBJECTIVE: Monoamine oxidase A is a mitochondrial enzyme involved in the degradation of certain neurotransmitter amines: serotonin and norepinephrine. As for its role in aggression, impulsivity, suicide and mood liability, monoamine oxidase A can be considered a functional candidate in borderline personality disorder. METHODS: To test for this hypothesis we genotyped two polymorphic markers in monoamine oxidase A gene, a promoter VNTR and an rs6323 (T941G) in exon 8, in 111 Caucasian borderline personality disorder patients and 289 Caucasian healthy controls. Association analyses using individual marker and haplotype data were performed by a program of COCAPHASE in UNPHASED (MRC Human Genome Mapping Project Resource Centre, Cambridge, UK). RESULTS: We found that the borderline personality disorder patients had a high frequency of the high activity VNTR alleles (chi=4.696, P=0.03) and a low frequency of the low activity haplotype (chi=5.089, P=0.02). CONCLUSION: These results show that the monoamine oxidase A gene may play an important role in the etiological development of the borderline personality disorder.     

Monoamine oxidase activity of rat organs during experimental pneumococcus infection

Summary Rats infected with Pneumococcus were noted to have a reduction of monoaminoxi dase in the brain, liver, and lung homogenates, which progressed with the development of the infection. No significant reduction in the activity of this enzyme in the kidneys was noted. The secretion of 5-oxyindolacetic acid with the urine in pneumococcus-infected rats did not differ from that seen in the control animals.Presented by Member of the Academy of Medical Sciences USSR, L. A. Zil'ber Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 61, No. 1, pp. 48–50, January, 1966     

单胺氧化酶B——治疗神经元退行性变的可能靶点

单胺氧化酶B(MAOB)是一类黄素依赖性蛋白酶,由520个氨基酸构成,通过C端的跨膜螺旋结合于线粒体外膜。MAOB基因定位于X染色体,核心启动子位于-246/-99。MAOB基因表达受多种因素调控。MAOB在多巴胺代谢途径中发挥重要作用。可将多巴胺降解为二羟苯乙酸,并生成过氧化氢。MAOB基因敲除小鼠对神经毒素1-甲基-4-苯基-1,2,3,6-四羟嘧啶(MPTP)具有耐受性。MAOB分布于脑内特定脑区,在多种神经元退行性疾病中发现脑内MAOB活性升高。MAOB可能发挥着调节氧化应激、参与神经元退行性变等作用。     

Monoamine oxidase activity and distribution in marmoset brain: implications for MPTP toxicity

This study describes the histochemical localisation of monoamine oxidase (MAO) in marmoset brain. No MAO A staining was observed but MAO B was found in many areas, with medium intensity of staining in the substantia nigra, and high intensity staining in the striatum and nucleus accumbens, among other regions. The high activity in the nigrostriatal tract, compared with the rat, may partially explain the greater sensitivity of the marmoset to MPTP toxicity. As in the rat, high activity was present in the raphe nuclei. However, unlike the rat, no enrichment of MAO B was observed in blood vessels or ventricular linings.