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AIMS/HYPOTHESIS: Nicotinamide-N-methyltransferase (NNMT) was recently shown to be upregulated in mouse models of insulin resistance and obesity. So far, it is unknown whether NNMT is regulated in human disease. We have explored the hypothesis that white adipose tissue (WAT) NNMT expression and plasma 1-methylnicotinamide (MNA) concentration are increased in human insulin resistance and type 2 diabetes. METHODS: NNMT expression and plasma MNA were analysed in three groups of individuals: (1) 199 patients undergoing abdominal surgery; (2) 60 individuals on a 12-week exercise programme and (3) 55 patients on a two-step bariatric surgery programme. RESULTS: Patients with manifest type 2 diabetes have a significantly (approximately twofold) higher NNMT expression both in omental and subcutaneous WAT compared with controls. Notably, plasma MNA correlated significantly with WAT NNMT expression in patients with type 2 diabetes (women, r = 0.59, p < 0.001; men, r = 0.61, p < 0.001) but not in healthy control individuals. In insulin-resistant individuals, there was an inverse correlation between insulin sensitivity and plasma MNA (r = 0.44, p = 0.01) or adipose tissue NNMT mRNA (r = 0.64, p < 0.001). The latter association was confirmed in a second cohort (n = 60, r = 0.78, p < 0.001). Interventions improving insulin sensitivity--exercise and bariatric surgery--were associated with a significant (p < 0.001) reduction in WAT NNMT expression. Bariatric surgery was also associated with a significant decrease in plasma MNA. CONCLUSIONS/INTERPRETATION: We demonstrate that WAT NNMT expression is regulated in human insulin resistance and type 2 diabetes and that plasma MNA correlates with increased tissue NNMT expression and the degree of insulin resistance, making it a potential biomarker for loss of insulin sensitivity.
Assuntos
Diabetes Mellitus Tipo 2/sangue , Resistência à Insulina , Niacinamida/análogos & derivados , Nicotinamida N-Metiltransferase/metabolismo , Obesidade/sangue , RNA Mensageiro/metabolismo , Gordura Subcutânea/enzimologia , Adulto , Idoso , Cirurgia Bariátrica , Biomarcadores/sangue , Estudos de Casos e Controles , Estudos Transversais , Diabetes Mellitus Tipo 2/diagnóstico , Diabetes Mellitus Tipo 2/fisiopatologia , Terapia por Exercício , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Niacinamida/sangue , Nicotinamida N-Metiltransferase/genética , Obesidade/diagnóstico , Obesidade/terapia , RNA Mensageiro/genética , Fatores de Tempo , Resultado do Tratamento , Adulto JovemRESUMO
The discovery of potent benzimidazole stearoyl-CoA desaturase (SCD1) inhibitors by ligand-based virtual screening is described. ROCS 3D-searching gave a favorable chemical motif that was subsequently optimized to arrive at a chemical series of potent and promising SCD1 inhibitors. In particular, compound SAR224 was selected for further pharmacological profiling based on favorable in vitro data. After oral administration to male ZDF rats, this compound significantly decreased the serum fatty acid desaturation index, thus providing conclusive evidence for SCD1 inhibition in vivo by SAR224.
Assuntos
Amidas/química , Benzimidazóis/química , Inibidores Enzimáticos/química , Estearoil-CoA Dessaturase/antagonistas & inibidores , Tiofenos/química , Amidas/metabolismo , Amidas/farmacocinética , Animais , Benzimidazóis/síntese química , Disponibilidade Biológica , Células CACO-2 , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacocinética , Meia-Vida , Humanos , Ligantes , Masculino , Camundongos , Ligação Proteica , Ratos , Ratos Zucker , Estearoil-CoA Dessaturase/metabolismo , Relação Estrutura-Atividade , Tiofenos/síntese químicaRESUMO
Quality control of biopharmaceuticals such as monoclonal antibodies (mAbs) has been evolving and becoming more challenging as the requirements of the regulatory agencies increase due to the demanding complexity of products under evaluation. Mass Spectrometry (MS)-based methods such as the multi-attribute method (MAM) are being explored to achieve a deeper understanding of the attributes critical for the safety, efficacy, and quality of these products. MAM uses high mass accuracy/high-resolution MS data that enables the direct and simultaneous monitoring of relevant product quality attributes (PQAs, in particular, chemical modifications) in a single workflow, replacing several orthogonal methods, reducing time and costs associated with these assays. Here we describe a MAM implementation process using a QTOF high resolution platform. Method implementation was accomplished using NIST (National Institute for Standards and Technology) mAb reference material and an in-process mAb sample. PQAs as glycosylation profiles, methionine oxidation, tryptophan dioxidation, asparagine deamidation, pyro-Glu at N-terminal and glycation were monitored. Focusing on applications that require batch analysis and high-throughput, sample preparation and LC-MS parameters troubleshooting are discussed. This MAM workflow was successfully explored as reference analytical tool for comprehensive characterization of a downstream processing (DSP) polishing platform and for a comparability study following technology transfer between different laboratories.
Assuntos
Produtos Biológicos/química , Espectrometria de Massas/métodos , Anticorpos Monoclonais/química , Cromatografia Líquida/métodos , Controle de Qualidade , Projetos de Pesquisa , Tripsina/química , Fluxo de TrabalhoRESUMO
More than 370 biotherapeutics drug products have been approved by regulatory agencies on the US and EU markets and this industry continues to expand. Process change and optimization is necessary to develop new effective biologics in a cost effective and productive way. Consequently, improvement of analytical techniques is required for better product characterization according to Quality by Design (QbD) approach recommended by regulatory agencies. Recently, multi-attribute method (MAM) has emerged to meet such demands using mass spectrometry coupled to liquid chromatography (LC-MS). However, traditional sample preparation or data processing would not be suitable to guide process development, because one of the common challenges during development of analytical platforms is instrument or method variability which can cause deviation in results. Here, we show a new automated analytical platform for MAM implemented on 3 different sites: the components of MAM platform include automated sample preparation, LC-MS based MAM, and data treatment automation. To our knowledge, this is the first study to show global harmonization on automated MAM platforms and the inter-sites comparability including the automated sample preparation and LC-MS instrument. Also, we demonstrate the applicability of MAM to support cell line development, cell culture process development and downstream process development. We expect that this MAM platform will effectively guide process development across multiple projects.
Assuntos
Anticorpos Monoclonais , Automação/métodos , Cromatografia Líquida/métodos , Espectrometria de Massas/métodos , Animais , Anticorpos Monoclonais/análise , Anticorpos Monoclonais/química , Anticorpos Monoclonais/isolamento & purificação , Anticorpos Monoclonais/metabolismo , Células CHO , Cricetinae , Cricetulus , Interações Hidrofóbicas e Hidrofílicas , Projetos de PesquisaRESUMO
OBJECTIVE: Ectopic fat deposition is associated with increased tissue production of ceramides. Recent genetic mouse studies suggest that specific sphingolipid C16:0 ceramide produced by ceramide synthase 6 (CerS6) plays an important role in the development of insulin resistance. However, the therapeutic potential of CerS6 inhibition not been demonstrated. Therefore, we pharmacologically investigated the selective ablation of CerS6 using antisense oligonucleotides (ASO) in obese insulin resistance animal models. METHODS: We utilized ASO as therapeutic modality, CerS6 ASO molecules designed and synthesized were initially screened for in-vitro knock-down (KD) potency and cytotoxicity. ASOs with >85% inhibition of CerS6 mRNA were selected for further investigations. Most promising ASOs verified for in-vivo KD efficacy in healthy mice. CerS6 ASO (AAGATGAGCCGCACC) was found most active with hepatic reduction of CerS6 mRNA expression. Prior to longitudinal metabolic studies, we performed a dose titration target engagement analysis with CerS6 ASO in healthy mice to select the optimal dose. Next, we utilized leptin deficiency ob/ob and high fat diet (HFD) induced obese mouse models for pharmacological efficacy study. RESULTS: CerS6 expression were significantly elevated in the liver and brown adipose, this was correlated with significantly elevated C16:0 ceramide concentrations in plasma and liver. Treatment with CerS6 ASO selectively reduced CerS6 expression by â¼90% predominantly in the liver and this CerS6 KD resulted in a significant reduction of C16:0 ceramide by about 50% in both liver and plasma. CerS6 KD resulted in lower body weight gain and accompanied by a significant reduction in whole body fat and fed/fasted blood glucose levels (1% reduction in HbA1c). Moreover, ASO-mediated CerS6 KD significantly improved oral glucose tolerance (during oGTT) and mice displayed improved insulin sensitivity. Thus, CerS6 appear to play an important role in the development of obesity and insulin resistance. CONCLUSIONS: Our investigations identified specific and selective therapeutic valid ASO for CerS6 ablation in in-vivo. CerS6 should specifically be targeted for the reduction of C16:0 ceramides, that results in amelioration of insulin resistance, hyperglycemia and obesity. CerS6 mediated C16:0 ceramide reduction could be a potentially attractive target for the treatment of insulin resistance, obesity and type 2 diabetes.
Assuntos
Ceramidas/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Obesidade/metabolismo , Oligonucleotídeos Antissenso/metabolismo , Esfingosina N-Aciltransferase/metabolismo , Tecido Adiposo Marrom/metabolismo , Animais , Glicemia/metabolismo , Dieta Hiperlipídica/efeitos adversos , Modelos Animais de Doenças , Técnicas de Silenciamento de Genes , Células Hep G2 , Humanos , Resistência à Insulina , Leptina/deficiência , Fígado/metabolismo , Masculino , Proteínas de Membrana/antagonistas & inibidores , Proteínas de Membrana/genética , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Obesos , Obesidade/etiologia , Oligonucleotídeos Antissenso/farmacologia , Esfingosina N-Aciltransferase/antagonistas & inibidores , Esfingosina N-Aciltransferase/genética , Tionucleotídeos , Aumento de PesoRESUMO
Antisense oligonucleotide knockdown (ASO-KD) of nicotinamide N-methyltransferase (NNMT) in high-fat diet (HFD)-fed mice has been reported to reduce weight gain and plasma insulin levels and to improve glucose tolerance. Using NNMT-ASO-KD or NNMT knockout mice (NNMT-/-), we tested the hypothesis that Nnmt deletion protects against diet-induced obesity and its metabolic consequences in males and females on obesity-inducing diets. We also examined samples from a human weight reduction (WR) study for adipose NNMT (aNNMT) expression and plasma 1-methylnicotinamide (MNAM) levels. In Western diet (WD)-fed female mice, NNMT-ASO-KD reduced body weight, fat mass, and insulin level and improved glucose tolerance. Although NNMT-/- mice fed a standard diet had no obvious phenotype, NNMT-/- males fed an HFD showed strongly improved insulin sensitivity (IS). Furthermore, NNMT-/- females fed a WD showed reduced weight gain, less fat, and lower insulin levels. However, no improved glucose tolerance was observed in NNMT-/- mice. Although NNMT expression in human fat biopsy samples increased during WR, corresponding plasma MNAM levels significantly declined, suggesting that other mechanisms besides aNNMT expression modulate circulating MNAM levels during WR. In summary, upon NNMT deletion or knockdown in males and females fed different obesity-inducing diets, we observed sex- and diet-specific differences in body composition, weight, and glucose tolerance and estimates of IS.
Assuntos
Intolerância à Glucose/metabolismo , Resistência à Insulina/fisiologia , Nicotinamida N-Metiltransferase/metabolismo , Obesidade/metabolismo , Animais , Composição Corporal/genética , Composição Corporal/fisiologia , Peso Corporal/genética , Peso Corporal/fisiologia , Dieta Hiperlipídica/efeitos adversos , Intolerância à Glucose/genética , Resistência à Insulina/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Nicotinamida N-Metiltransferase/genética , Obesidade/genéticaRESUMO
Physicochemical properties of peptides need to be compatible with the manufacturing process and formulation requirements to ensure developability toward the commercial drug product. This aspect is often disregarded and only evaluated late in discovery, imposing a high risk for delays in development, increased costs, and finally for the project in general. Here, we report a case study of early physicochemical peptide characterization and optimization of dual glucagon-like peptide 1/glucagon receptor agonists toward specific formulation requirements. Aggregation issues which were observed at acidic pH in the presence of phenolic preservatives could be eliminated by modification of the peptide sequence, and chemical stability issues were significantly improved by addition of stabilizing formulation excipients. We describe structural, analytical, and biophysical characterization in different compositions to analyze the effect of pH and formulation excipients on physical and chemical stability. Molecular models have been generated to rationalize peptide stability behavior based on computed physicochemical descriptors and interactions with excipients. To conclude these studies, a general roadmap is proposed how to assess and optimize early physicochemical peptide properties in a sophisticated way by combining experimental and in silico profiling to provide stable peptide drugs under relevant formulation conditions at the end of discovery.
Assuntos
Desenvolvimento de Medicamentos/métodos , Descoberta de Drogas/métodos , Peptídeos/química , Simulação por Computador , Estabilidade de Medicamentos , Excipientes/química , Peptídeo 1 Semelhante ao Glucagon/agonistas , Concentração de Íons de Hidrogênio , Simulação de Dinâmica Molecular , Peptídeos/farmacologia , Conservantes Farmacêuticos/química , Receptores de Glucagon/agonistasRESUMO
Complex mixtures of high molecular weight fractions of pooled neutral human milk oligosaccharides (obtained via gel permeation chromatography) have been investigated. The subfractions were each permethylated and analyzed by high-resolution mass spectrometry, using matrix-assisted laser desorption/ionization (MALDI)-Fourier transform ion cyclotron resonance (FTICR) mass spectrometry, in order to investigate their oligosaccharide compositions. The obtained spectra reveal that human milk contains more complex neutral oligosaccharides than have been described previously; the data show that these oligosaccharides can be highly fucosylated, and that their poly-N-acetyllactosamine cores are substituted with up to 10 fucose residues on a an oligosaccharide that has 7-N-acetyllactosamine units. This is the first report of the existence in human milk of this large range of highly fucosylated oligosaccharides which possess novel, potentially immunologically active structures.
RESUMO
Fatty acid esters of hydroxylated fatty acids (FAHFAs) were discovered as a novel class of endogenous mammalian lipids whose profound effects on metabolism have been shown. In the current study, in vitro and in vivo the metabolic effects of two of these FAHFAs, namely palmitic acid-5- (or -9) -hydroxy-stearic acid (5- or 9-PAHSA, respectively) were profiled. In DIO mice fed with differentially composed low- or high-fat diets, acute and subchronic treatment with 5-PAHSA and 9-PAHSA alone, or in combination, did not significantly improve the deranged metabolic status. Neither racemic 5- or 9-PAHSA, nor the enantiomers were able to: (1) increase basal or insulin-stimulated glucose uptake in vitro, (2) stimulate GLP-1 release from GLUTag cells, or (3) induce GSIS in rat, mouse, or human islets or in a human pancreatic ß cell line. Therefore, our data do not support the further development of PAHSAs or their derivatives for the control of insulin resistance and hyperglycemia.
Assuntos
Hiperglicemia/tratamento farmacológico , Resistência à Insulina , Ilhotas Pancreáticas , Obesidade , Ácido Palmítico , Ácidos Esteáricos , Animais , Dieta com Restrição de Gorduras , Dieta Hiperlipídica , Peptídeo 1 Semelhante ao Glucagon/metabolismo , Glucose/metabolismo , Células HEK293 , Humanos , Ilhotas Pancreáticas/efeitos dos fármacos , Ilhotas Pancreáticas/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Modelos Animais , Obesidade/tratamento farmacológico , Obesidade/metabolismo , Ácido Palmítico/administração & dosagem , Ácido Palmítico/farmacologia , Ratos , Ratos Sprague-Dawley , Ácidos Esteáricos/administração & dosagem , Ácidos Esteáricos/farmacologiaRESUMO
Novel peptidic dual agonists of the glucagon-like peptide 1 (GLP-1) and glucagon receptor are reported to have enhanced efficacy over pure GLP-1 receptor agonists with regard to treatment of obesity and diabetes. We describe novel exendin-4 based dual agonists designed with an activity ratio favoring the GLP-1 versus the glucagon receptor. As result of an iterative optimization procedure that included molecular modeling, structural biological studies (X-ray, NMR), peptide design and synthesis, experimental activity, and solubility profiling, a candidate molecule was identified. Novel SAR points are reported that allowed us to fine-tune the desired receptor activity ratio and increased solubility in the presence of antimicrobial preservatives, findings that can be of general applicability for any peptide discovery project. The peptide was evaluated in chronic in vivo studies in obese diabetic monkeys as translational model for the human situation and demonstrated favorable blood glucose and body weight lowering effects.
Assuntos
Descoberta de Drogas , Receptor do Peptídeo Semelhante ao Glucagon 1/agonistas , Receptores de Glucagon/agonistas , Relação Dose-Resposta a Droga , Composição de Medicamentos , Espaço Extracelular/metabolismo , Receptor do Peptídeo Semelhante ao Glucagon 1/química , Células HEK293 , Humanos , Modelos Moleculares , Domínios Proteicos , Receptores de Glucagon/química , Solubilidade , Relação Estrutura-AtividadeRESUMO
Nicotinamide N-methyltransferase (NNMT) is a cytosolic enzyme that catalyzes the transfer of a methyl group from the co-factor S-adenosyl-L-methionine (SAM) onto the substrate, nicotinamide (NA) to form 1-methyl-nicotinamide (MNA). Higher NNMT expression and MNA concentrations have been associated with obesity and type-2 diabetes. Here we report a small molecule analog of NA, JBSNF-000088, that inhibits NNMT activity, reduces MNA levels and drives insulin sensitization, glucose modulation and body weight reduction in animal models of metabolic disease. In mice with high fat diet (HFD)-induced obesity, JBSNF-000088 treatment caused a reduction in body weight, improved insulin sensitivity and normalized glucose tolerance to the level of lean control mice. These effects were not seen in NNMT knockout mice on HFD, confirming specificity of JBSNF-000088. The compound also improved glucose handling in ob/ob and db/db mice albeit to a lesser extent and in the absence of weight loss. Co-crystal structure analysis revealed the presence of the N-methylated product of JBSNF-000088 bound to the NNMT protein. The N-methylated product was also detected in the plasma of mice treated with JBSNF-000088. Hence, JBSNF-000088 may act as a slow-turnover substrate analog, driving the observed metabolic benefits.
Assuntos
Inibidores Enzimáticos/uso terapêutico , Doenças Metabólicas/tratamento farmacológico , Doenças Metabólicas/enzimologia , Nicotinamida N-Metiltransferase/metabolismo , Animais , Peso Corporal/efeitos dos fármacos , Diabetes Mellitus Tipo 2/tratamento farmacológico , Diabetes Mellitus Tipo 2/enzimologia , Dieta Hiperlipídica/efeitos adversos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Nicotinamida N-Metiltransferase/antagonistas & inibidoresRESUMO
Diabetic nephropathy (DN) is a major cause of end-stage renal disease, and therapeutic options for preventing its progression are limited. To identify novel therapeutic strategies, we studied protective factors for DN using proteomics on glomeruli from individuals with extreme duration of diabetes (l50 years) without DN and those with histologic signs of DN. Enzymes in the glycolytic, sorbitol, methylglyoxal and mitochondrial pathways were elevated in individuals without DN. In particular, pyruvate kinase M2 (PKM2) expression and activity were upregulated. Mechanistically, we showed that hyperglycemia and diabetes decreased PKM2 tetramer formation and activity by sulfenylation in mouse glomeruli and cultured podocytes. Pkm-knockdown immortalized mouse podocytes had higher levels of toxic glucose metabolites, mitochondrial dysfunction and apoptosis. Podocyte-specific Pkm2-knockout (KO) mice with diabetes developed worse albuminuria and glomerular pathology. Conversely, we found that pharmacological activation of PKM2 by a small-molecule PKM2 activator, TEPP-46, reversed hyperglycemia-induced elevation in toxic glucose metabolites and mitochondrial dysfunction, partially by increasing glycolytic flux and PGC-1α mRNA in cultured podocytes. In intervention studies using DBA2/J and Nos3 (eNos) KO mouse models of diabetes, TEPP-46 treatment reversed metabolic abnormalities, mitochondrial dysfunction and kidney pathology. Thus, PKM2 activation may protect against DN by increasing glucose metabolic flux, inhibiting the production of toxic glucose metabolites and inducing mitochondrial biogenesis to restore mitochondrial function.
Assuntos
Diabetes Mellitus/metabolismo , Nefropatias Diabéticas/metabolismo , Glucose/metabolismo , Potencial da Membrana Mitocondrial , Mitocôndrias/metabolismo , Podócitos/metabolismo , Piruvato Quinase/genética , Idoso , Idoso de 80 Anos ou mais , Animais , Western Blotting , Linhagem Celular , Diabetes Mellitus Experimental , Feminino , Imunofluorescência , Técnicas de Silenciamento de Genes , Glicólise , Humanos , Rim/metabolismo , Glomérulos Renais/metabolismo , Masculino , Metabolômica , Camundongos , Camundongos Knockout , Pessoa de Meia-Idade , Óxido Nítrico Sintase Tipo III/genética , Biogênese de Organelas , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/genética , Proteômica , Piruvato Quinase/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Reação em Cadeia da Polimerase em Tempo RealRESUMO
Dietary protein intake is linked to an increased incidence of type 2 diabetes (T2D). Although dietary protein dilution (DPD) can slow the progression of some aging-related disorders, whether this strategy affects the development and risk for obesity-associated metabolic disease such as T2D is unclear. Here, we determined that DPD in mice and humans increases serum markers of metabolic health. In lean mice, DPD promoted metabolic inefficiency by increasing carbohydrate and fat oxidation. In nutritional and polygenic murine models of obesity, DPD prevented and curtailed the development of impaired glucose homeostasis independently of obesity and food intake. DPD-mediated metabolic inefficiency and improvement of glucose homeostasis were independent of uncoupling protein 1 (UCP1), but required expression of liver-derived fibroblast growth factor 21 (FGF21) in both lean and obese mice. FGF21 expression and secretion as well as the associated metabolic remodeling induced by DPD also required induction of liver-integrated stress response-driven nuclear protein 1 (NUPR1). Insufficiency of select nonessential amino acids (NEAAs) was necessary and adequate for NUPR1 and subsequent FGF21 induction and secretion in hepatocytes in vitro and in vivo. Taken together, these data indicate that DPD promotes improved glucose homeostasis through an NEAA insufficiency-induced liver NUPR1/FGF21 axis.
Assuntos
Diabetes Mellitus Tipo 2/metabolismo , Proteínas Alimentares/administração & dosagem , Fígado/metabolismo , Tecido Adiposo/metabolismo , Adulto , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Metabolismo dos Carboidratos , Proteínas de Ligação a DNA/metabolismo , Fatores de Crescimento de Fibroblastos/metabolismo , Glucose/metabolismo , Hepatócitos/metabolismo , Homeostase , Humanos , Metabolismo dos Lipídeos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas de Neoplasias/metabolismo , Obesidade/metabolismo , Fenótipo , Proteína Desacopladora 1/metabolismoRESUMO
Pathological pain associated either with peripheral tissue damage and inflammation (inflammatory pain) or peripheral nerve injury (neuropathic pain) is characterized by persistent pain hypersensitivity. This hypersensitivity is believed to be mediated by sensitization of nociceptors and spinal dorsal horn neurons leading to hyperalgesia and allodynia. Changes of protein expression and/or phosphorylation are known to contribute to the development of this hyperexcitability of the nociceptive system. In the present study we analyzed protein patterns in the spinal cord following paw inflammation or sciatic nerve injury using two-dimensional (2D) gel electrophoresis combined with MALDI-TOF mass spectrometry. 2D-PAGE revealed nine and five regulated proteins following paw inflammation and sciatic nerve damage, respectively. These regulated proteins had not been identified previously with other methods. There was no overlap of regulated proteins between models except for the small heat shock protein alpha-crystallin, which was decreased in both models. In conclusion, this study illustrates that employment of the proteomic 2D-PAGE approach allows for identification of novel regulated proteins that may be involved in the central sensitization and possibly manifestation of chronic pain.
Assuntos
Inflamação/fisiopatologia , Neuralgia/fisiopatologia , Proteômica , Medula Espinal/química , Medula Espinal/citologia , Animais , Modelos Animais de Doenças , Eletroforese em Gel Bidimensional , Membro Posterior/patologia , Inflamação/induzido quimicamente , Ligadura , Masculino , Ratos , Ratos Sprague-Dawley , Nervo Isquiático/lesões , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Zimosan/farmacologiaRESUMO
OBJECTIVE: Type 2 diabetes arises from insulin resistance of peripheral tissues followed by dysfunction of ß-cells in the pancreas due to metabolic stress. Both depletion and supplementation of neutral amino acids have been discussed as strategies to improve insulin sensitivity. Here we characterise mice lacking the intestinal and renal neutral amino acid transporter B(0)AT1 (Slc6a19) as a model to study the consequences of selective depletion of neutral amino acids. METHODS: Metabolic tests, analysis of metabolite levels and signalling pathways were used to characterise mice lacking the intestinal and renal neutral amino acid transporter B(0)AT1 (Slc6a19). RESULTS: Reduced uptake of neutral amino acids in the intestine and loss of neutral amino acids in the urine causes an overload of amino acids in the lumen of the intestine and reduced systemic amino acid availability. As a result, higher levels of glucagon-like peptide 1 (GLP-1) are produced by the intestine after a meal, while the liver releases the starvation hormone fibroblast growth factor 21 (FGF21). The combination of these hormones generates a metabolic phenotype that is characterised by efficient removal of glucose, particularly by the heart, reduced adipose tissue mass, browning of subcutaneous white adipose tissue, enhanced production of ketone bodies and reduced hepatic glucose output. CONCLUSIONS: Reduced neutral amino acid availability improves glycaemic control. The epithelial neutral amino acid transporter B(0)AT1 could be a suitable target to treat type 2 diabetes.
RESUMO
Since long-term hyperexcitability of nociceptive neurons in the spinal cord has been suggested to be caused and maintained by changes of protein expression we assessed protein patterns in lumbar spinal cord during a zymosan induced paw inflammation employing two-dimensional (2D) gel electrophoresis. 2D PAGE revealed a time-dependent breakdown of scaffolding proteins one of which was neurofilament light chain (NFL) protein, which has been previously found to be important for axonal architecture and transport. Nociception induced breakdown of NFL in the spinal cord and dorsal root ganglias was prevented by pretreatment of the animals with a single dose of the specific inhibitor of the protease calpain (MDL-28170) which has been shown to be the primary protease involved in neurofilament degradation in neurodegenerative diseases. Treatment with the calpain inhibitor also provided anti-inflammatory and anti-hyperalgesic effects in the zymosan-induced paw inflammation model irrespective of whether the drug was administered systemically (i.p.) or delivered onto the lumbar spinal cord. This suggests that the activation of calpain is involved in the sensitization of nociceptive neurons what is partly due to neurofilament breakdown but cleavage of other calpain substrates may also be involved. Our results indicate that inhibition of pathological calpain activity may present an interesting novel drug target in the treatment of pain and inflammation.
Assuntos
Inibidores de Cisteína Proteinase/uso terapêutico , Dipeptídeos/uso terapêutico , Hiperalgesia/tratamento farmacológico , Inflamação/metabolismo , Proteínas de Neurofilamentos/metabolismo , Medula Espinal/efeitos dos fármacos , Animais , Calpaína/metabolismo , Relação Dose-Resposta a Droga , Eletroforese em Gel Bidimensional/métodos , Imunofluorescência/métodos , Immunoblotting/métodos , Inflamação/induzido quimicamente , Masculino , Medição da Dor , RNA Mensageiro/biossíntese , Ratos , Ratos Sprague-Dawley , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Fatores de Tempo , ZimosanRESUMO
Underivatized neutral oligosaccharides from human milk were analyzed by nano-electrospray ionization (ESI) using a quadrupole ion trap mass spectrometer (QIT-MS) in the negative-ion mode. Under these conditions neutral oligosaccharides are observed as deprotonated molecules [M-H]- with high intensity. CID-experiments of these species with the charge localized at the reducing end lead to C-type fragment ions forming a "new" reducing end. Fragmentations are accompanied by cross-ring cleavages that yield information about linkages of internal monosaccharides. Several isomeric compounds with distinct structural features, such as different glycosidic linkages, fucosylation and branching sites were investigated. The rules governing the fragmentation behavior of this class of oligosaccharides were elucidated and tested for a representative number of certain isomeric glycoforms using the MS/MS and MS(n) capabilities of the QIT. On the basis of the specific fragmentation behavior of deprotonated molecules, the position of fucoses and the linkage type (Gal beta-->3 GlcNAc or Gal beta1-->4 GlcNAc) could be determined and linear and branched could be differentiated. Rules could be established which can be applied in further investigations of these types of oligosaccharides even from heterogenous mixtures.
Assuntos
Leite Humano/química , Oligossacarídeos/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Feminino , Fucose/química , Glicosídeos/química , Humanos , Isomerismo , Nanotecnologia , Radioisótopos de OxigênioRESUMO
A complex mixture of isomeric neutral oligosaccharides from pooled human milk was analyzed by nano-electrospray ionization (ESI) in a quadrupole ion trap mass spectrometer (QIT-MS) in the negative ion mode. Since deprotonated molecules of neutral oligosaccharides follow distinct fragmentation rules, which have been elucidated by using model compounds (see [1]), spectra obtained from consecutive CID experiments allowed the differentiation of isomers out of this highly complex mixture. With this method new human milk oligosaccharides of previously unknown isomeric structures have been identified, e.g., the occurence of three isomeric fucosylated lacto-N-hexaoses could be determined precisely, which have not been described before: (1) Fuc (alpha1-->2) Gal (beta1-->3) GlcNac (beta1-->3) Gal (beta1-->4) GlcNac (beta1-->3) Gal (beta1-->4) Glc, (2) Gal (beta1-->4) GlcNAc [(alpha1-->3) Fuc] (beta1-->3) Gal (beta1-->4) GlcNac (beta1-->3) Gal (beta1-->4) Glc, (3) Gal (beta1-->4) GlcNAc (beta1-->3) Gal (beta1-->4) GlcNac [(alpha1-->3) Fuc] (beta1-->3) Gal (beta1-->4) Glc.
Assuntos
Leite Humano/química , Oligossacarídeos/química , Espectrometria de Massas por Ionização por Electrospray/métodos , Feminino , Fucose/química , Glicosídeos/química , Humanos , Isomerismo , Nanotecnologia , Radioisótopos de OxigênioRESUMO
Stearoyl-CoA desaturase (SCD1) is linked to the pathogenesis of obesity, dyslipidemia and type 2 diabetes. It is the rate-limiting enzyme in the synthesis of monounsaturated 16:1 n-7 and 18:1 n-9 fatty acyl-CoAs and catalyzes an essential part of lipogenesis. Here, we describe the identification, in vitro properties and in vivo efficacy of a novel class of heterocyclic small molecule hexahydro-pyrrolopyrrole SCD1 inhibitors. SAR707, a compound representative for the series, was optimized to high in vitro potency, selectivity and favorable overall properties in enzymatic and cellular assays. In vivo, this compound reduced serum desaturation index, decreased body weight gain and improved lipid parameters and blood glucose levels of obese Zucker diabetic fatty rats treated for 4 weeks in a chronic study. In parallel, fissures of the eye lid, alopecia and inflammation of the skin were observed from day 11 on in all animals treated with the same metabolically active dose. In summary, we described in vitro and in vivo properties of a novel, potent and selective SCD1 inhibitor that improved body weight, blood glucose and triglycerides in an animal model of obesity, type 2 diabetes and dyslipidemia. However, the favorable in vivo properties of systemic SCD1 inhibition shown in our study were accompanied by dose-dependently occurring adverse target-related effects observed in skin. Thus, systemic SCD1 inhibition by small molecules might therefore not represent a feasible approach for the treatment of chronic metabolic diseases.