There is a critical need for new mechanism-of-action drugs that reduce the burden of obesity and associated chronic metabolic comorbidities. A potentially novel target to treat obesity and type 2 diabetes is nicotinamide-N-methyltransferase (NNMT), a cytosolic enzyme with newly identified roles in cellular metabolism and energy homeostasis. To validate NNMT as an anti-obesity drug target, we investigated the permeability, selectivity, mechanistic, and physiological properties of a series of small molecule NNMT inhibitors. Membrane permeability of NNMT inhibitors was characterized using parallel artificial membrane permeability and Caco-2 cell assays. Selectivity was tested against structurally-related methyltransferases and nicotinamide adenine dinucleotide (NAD) salvage pathway enzymes. Effects of NNMT inhibitors on lipogenesis and intracellular levels of metabolites, including NNMT reaction product 1-methylnicotianamide (1-MNA) were evaluated in cultured adipocytes. Effects of a potent NNMT inhibitor on obesity measures and plasma lipid were assessed in diet-induced obese mice fed a high-fat diet. Methylquinolinium scaffolds with primary amine substitutions displayed high permeability from passive and active transport across membranes. Importantly, methylquinolinium analogues displayed high selectivity, not inhibiting related SAM-dependent methyltransferases or enzymes in the NAD salvage pathway. NNMT inhibitors reduced intracellular 1-MNA, increased intracellular NAD and S-(5'-adenosyl)-l-methionine (SAM), and suppressed lipogenesis in adipocytes. Treatment of diet-induced obese mice systemically with a potent NNMT inhibitor significantly reduced body weight and white adipose mass, decreased adipocyte size, and lowered plasma total cholesterol levels. Notably, administration of NNMT inhibitors did not impact total food intake nor produce any observable adverse effects. These results support development of small molecule NNMT inhibitors as therapeutics to reverse diet-induced obesity and validate NNMT as a viable target to treat obesity and related metabolic conditions. Increased flux of key cellular energy regulators, including NAD and SAM, may potentially define the therapeutic mechanism-of-action of NNMT inhibitors.
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http://dx.doi.org/10.1016/j.bcp.2017.11.007 | DOI Listing |
Arch Pharm Res
December 2024
Department of Biomedical Science, College of Natural Science, Chosun University, Gwangju, 61452, Republic of Korea.
Cellular metabolism-related epigenetic modulation plays a pivotal role in the maintenance of cellular homeostasis. Nicotinamide N-methyltransferase (NNMT) serves as a crucial link between cellular metabolism and epigenetics by catalyzing nicotinamide methylation using the universal methyl donor S-adenosyl-L-methionine. This direct connection bridges the methylation-mediated one-carbon metabolism with nicotinamide adenine dinucleotide levels.
View Article and Find Full Text PDFInt Immunopharmacol
December 2024
Key Lab of Aquatic Training Monitoring and Intervention of General Administration of Sport of China, Physical Education College, Jiangxi Normal University, Nanchang 330022, Jiangxi Province, China. Electronic address:
Emerging research has positioned Nicotinamide N-methyltransferase (NNMT) as a key player in oncology, with its heightened expression frequently observed across diverse cancers. This increased presence is tightly linked to tumor initiation, proliferation, and metastasis. The enzymatic function of NNMT is centered on the methylation of nicotinamide (NAM), utilizing S-adenosylmethionine (SAM) as the methyl donor, which results in the generation of S-adenosyl-L-homocysteine (SAH) and methyl nicotinamide (MNAM).
View Article and Find Full Text PDFAnal Chem
September 2024
Division of Molecular Genetics, Cancer and Stem Cell Research Program, Cancer Research Institute, Kanazawa University, Kakuma-machi, Kanazawa, Ishikawa 920-1192, Japan.
Metabolic abnormalities play a pivotal role in various pathological conditions, necessitating the quantification of specific metabolites for diagnosis. While mass spectrometry remains the primary method for metabolite measurement, its limited throughput underscores the need for biosensors capable of rapid detection. Previously, we reported that pillar[6]arene with 12 carboxylate groups (P6AC) forms host-guest complexes with 1-methylnicotinamide (1-MNA), which is produced in vivo by nicotinamide -methyltransferase (NNMT).
View Article and Find Full Text PDFDiabetes Obes Metab
November 2024
Ridgeline Therapeutics, Houston, Texas, USA.
Aim: To assess the effects of a small-molecule nicotinamide N-methyltransferase (NNMT) inhibitor, 5A1MQ, on body composition, metabolic variables, fatty liver pathologies, and circulating biomarkers in diet-induced obese (DIO) mice, and characterize its plasma pharmacokinetics (PK) and tissue distribution in vivo.
Materials And Methods: DIO mice were administered vehicle or 5A1MQ once daily for 28 days. Longitudinal measures of body composition, blood glucose and plasma insulin levels, and terminal measures of liver histopathology and serum markers, were evaluated.
J Immunother Cancer
July 2024
Department of Urology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangdong Provincial Clinical Research Center for Urological Diseases, Guangzhou, Guangdong, P.R. China
Background: This study comprehensively investigates the association between the expression of nicotinamide N-methyltransferase (NNMT) and clinical outcomes of urothelial bladder cancer (UBC), as well as the molecular mechanisms by which NNMT in cancer-associated fibroblast (CAF) modulates tumor progression and immunotherapy resistance in UBC.
Methods: Single-cell transcriptomic analyses, immunohistochemical and immunofluorescence assays were performed on bladder cancer samples to validate the relationship between NNMT expression and clinical outcomes. A series of experiments, including chromatin immunoprecipitation assay, liquid chromatography tandem mass spectrometry assay, and CRISPR‒Cas9 (Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-associated protein 9) knockout, together with models, have been established to determine the molecular functions of NNMT in CAFs in UBC.
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