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Brain-penetrant LSD1 inhibitors can block memory consolidation

Department of Radiology, Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Harvard Medical School, Charlestown, MA 02129, United States.
ACS Chemical Neuroscience (Impact Factor: 4.21). 02/2012; 3(2):120-128. DOI: 10.1021/cn200104y
Source: PubMed

ABSTRACT Modulation of histone modifications in the brain may represent a new mechanism for brain disorder therapy. Post-translational modifications of histones regulate gene expression, affecting major cellular processes such as proliferation, differentiation, and function. An important enzyme involved in one of these histone modifications is lysine specific demethylase 1 (LSD1). This enzyme is flavin-dependent and exhibits homology to amine oxidases. Parnate (2-phenylcyclopropylamine (2-PCPA); tranylcypromine) is a potent inhibitor of monoamine oxidases and derivatives of 2-PCPA have been used for development of selective LSD1 inhibitors based on the ability to form covalent adducts with flavin adenine dinucleotide (FAD). Here we report the synthesis and in vitro characterization of LSD1 inhibitors that bond covalently to FAD. The two most potent and selective inhibitors were used to demonstrate brain penetration when administered systemically to rodents. First, radiosynthesis of a positron-emitting analog was used to obtain preliminary bio-distribution data and whole brain time-activity curves. Second, we demonstrate that this series of LSD1 inhibitors is capable of producing a cognitive effect in a mouse model. By using a memory formation paradigm, novel object recognition, we show that LSD1 inhibition can abolish long-term memory formation without affecting short-term memory, providing further evidence for the importance of reversible histone methylation in the function of the nervous system.

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    • "A series of patent applications were disclosed by Oryzon and GSK describing N-substituted tranylcypromine derivatives [41] [42], several of them being highly selective for KDM1A over MAO A and MAO B. Two compounds from these series have been reported to have entered clinical studies [43] [44]. Neelamegam et al. found that compound RN-7 (Fig. 1) was over 300 times more potent against KDM1A over MAO A and B [45]. The authors were able to demonstrate an involvement of KDM1A as regulator of long-term memory formation implying a key function in the central nervous system. "
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    ABSTRACT: Histone demethylase KDM1A (also known as LSD1) has become an attractive therapeutic target for the treatment of cancer as well as other disorders such as viral infections. We report on the synthesis of compounds derived from the expansion of tranylcypromine as a chemical scaffold for the design of novel demethylase inhibitors. These compounds, which are substituted on the cyclopropyl core moiety, were evaluated for their ability to inhibit KDM1A in vitro as well as to function in cells by modulating the expression of Gfi-1b, a well recognized KDM1A target gene. The molecules were all found to covalently inhibit KDM1A and to become increasingly selective against human monoamine oxidases MAO A and MAO B through the introduction of bulkier substituents on the cyclopropylamine ring. Structural and biochemical analysis of selected trans isomers showed that the two stereoisomers are endowed with similar inhibitory activities against KDM1A, but form different covalent adducts with the FAD co-enzyme.
    European Journal of Medicinal Chemistry 08/2014; 86C:352-363. DOI:10.1016/j.ejmech.2014.08.068 · 3.43 Impact Factor
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    • ") (Fig. 2A, Table 1), which are similar to reported results using same peptide substrate [35]. RN-1, an irreversible inhibitor of KDM1A [36], showed an IC 50 value of 0.6 ± 0.05 lM in our KDM1A/KMT7 coupled assay (Fig. 2B). We were able to perform this assay in a 384-well format with a Z 0 factor of 0.72 (Fig. S3) [37] "
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    ABSTRACT: Covalent modifications, such as methylation and demethylation of lysine residues in histones, play important roles in chromatin dynamics and the regulation of gene expression. The lysine demethylases (KDMs) catalyze the demethylation of lysine residues on histone tails and are associated with diverse human diseases, including cancer, and are therefore proposed as targets for the therapeutic modulation of gene transcription. High-throughput assays have been developed to find inhibitors of KDMs, most of which are fluorescence-based assays. Here we report the development of a coupled scintillation proximity assay (SPA) for 3 KDMs: KDM1A (LSD1), KDM3A (JMJD1A) and KDM4A (JMJD2A). In this assay methylated peptides are first demethylated by a KDM, and a protein methyltransferase (PMT) is added to methylate the resulting peptide with tritiated SAM. The enzyme activities were optimized and kinetic parameters were determined. These robust coupled assays are suitable for screening KDMs in 384-well format (Z'-Factors of 0.70-0.80) facilitating discovery of inhibitors in the quest for cancer therapeutics.
    Analytical Biochemistry 07/2014; 463. DOI:10.1016/j.ab.2014.06.023 · 2.22 Impact Factor
    • "For instance, previous studies have shown that interpreting the results of novel object recognition studies is difficult because baseline emotional arousal affects apparent memory recall after drug treatment (Okuda et al., 2004). This could explain the surprising results of Neelamegam et al. (2012). Nonetheless , emerging evidence has now suggested that transient increases and decreases in histone lysine methylation levels is a critical step in long-term memory formation and suggests that memory formation requires a complex interaction between histone acetylation, histone lysine methylation , and DNA methylation within different brain regions of the memory circuit. "
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    ABSTRACT: Abstract Histone lysine methylation is a well-established transcriptional mechanism for the regulation of gene expression changes in eukaryotic cells and is now believed to function in neurons of the central nervous system to mediate the process of memory formation and behavior. In mature neurons, methylation of histone proteins can serve to both activate and repress gene transcription. This is in stark contrast to other epigenetic modifications, including histone acetylation and DNA methylation, which have largely been associated with one transcriptional state in the brain. In this review, we discuss the evidence for histone methylation mechanisms in the coordination of complex cognitive processes such as long-term memory formation and storage. In addition, we address the current literature highlighting the role of histone methylation in intellectual disability, addiction, schizophrenia, autism, depression, and neurodegeneration. Further, we discuss histone methylation within the context of other epigenetic modifications and the potential advantages of exploring this newly identified mechanism of cognition, emphasizing the possibility that this molecular process may provide an alternative locus for intervention in long-term psychopathologies that cannot be clearly linked to genes or environment alone.
    Reviews in the neurosciences 05/2013; 24(4):1-13. DOI:10.1515/revneuro-2013-0008 · 3.31 Impact Factor
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