Silencing alanine transaminase 2 in diabetic liver attenuates hyperglycemia by reducing gluconeogenesis from amino acids
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ABSTRACT:
PROVIDER: PRJNA822390 | ENA |
REPOSITORIES: ENA
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Project description:Hepatic gluconeogenesis from amino acids contributes significantly to diabetic hyperglycemia, but the molecular mechanisms involved are incompletely understood. Alanine transaminases (ALT1 and ALT2) catalyze the interconversion of alanine and pyruvate, which is required for gluconeogenesis from alanine. Hepatocyte-specific knockout of Gpt2 attenuated incorporation of 13C-alanine into newly synthesized glucose by hepatocytes. However, Gpt2 knockout in liver had no effect on glucose concentrations in lean mice, which may suggest that metabolic compensation is occurring.
2022-04-06 | GSE199975 | GEO
Project description: Not available
| S-EPMC9121396 | biostudies-literature
Project description:Objective: Insulin regulates amino acid metabolism. We investigated whether glycemia and 43 genetic risk variants for hyperglycemia/type 2 diabetes affect amino acid levels in a large population-based cohort. Subjects and Methods: A total of 9,371 non-diabetic or newly-diagnosed type 2 diabetic Finnish men from the population-based METSIM Study were studied. Proton NMR spectroscopy was used to measure plasma levels of 8 amino acids. Genotyping of 42 SNPs and mRNA microarray analysis from 200 subcutaneous adipose tissue samples were performed. Results: Increasing fasting and/or 2-hour plasma glucose levels were associated with increasing levels of alanine, valine, leucine, isoleucine, phenylalanine and tyrosine, and decreasing levels of histidine and glutamine. We also found significant correlations between insulin sensitivity (Matsuda ISI) and expression of genes regulating amino acid metabolism. Only one SNP (rs780094 in GCKR) of the 42 risk SNPs for type 2 diabetes or hyperglycemia was significantly associated with the levels of alanine, isoleucine, and glutamine. Conclusions : We observed that the levels of branched-chain, aromatic amino acids and alanine increased and the levels of glutamine and histidine decreased with increasing glycemia. These associations seemed to be mediated by insulin resistance, at least in part. GCKR rs780094 was significantly associated with several amino acids. Total RNA was obtained from subcutaneous fat biopsies from 200 people participating in the METSIM study (4 samples were replicated for a total of 204 arrays).
2012-04-01 | E-GEOD-32512 | biostudies-arrayexpress
Project description:Objective: Insulin regulates amino acid metabolism. We investigated whether glycemia and 43 genetic risk variants for hyperglycemia/type 2 diabetes affect amino acid levels in a large population-based cohort. Subjects and Methods: A total of 9,371 non-diabetic or newly-diagnosed type 2 diabetic Finnish men from the population-based METSIM Study were studied. Proton NMR spectroscopy was used to measure plasma levels of 8 amino acids. Genotyping of 42 SNPs and mRNA microarray analysis from 200 subcutaneous adipose tissue samples were performed. Results: Increasing fasting and/or 2-hour plasma glucose levels were associated with increasing levels of alanine, valine, leucine, isoleucine, phenylalanine and tyrosine, and decreasing levels of histidine and glutamine. We also found significant correlations between insulin sensitivity (Matsuda ISI) and expression of genes regulating amino acid metabolism. Only one SNP (rs780094 in GCKR) of the 42 risk SNPs for type 2 diabetes or hyperglycemia was significantly associated with the levels of alanine, isoleucine, and glutamine. Conclusions : We observed that the levels of branched-chain, aromatic amino acids and alanine increased and the levels of glutamine and histidine decreased with increasing glycemia. These associations seemed to be mediated by insulin resistance, at least in part. GCKR rs780094 was significantly associated with several amino acids.
2012-04-02 | GSE32512 | GEO
Project description:In diabetes, the kidney contributes to the development of diabetic hyperglycemia by increasing glucose reabsorption from the primary urine and by upregulating gluconeogenesis in the proximal tubule. However, these two processes are also controlled by the circadian clock, a mechanism that synchronizes a large number of specific renal functions with environmental daily cycles. Here, we investigated the (patho)physiological role of intrinsic renal tubule circadian clocks in the diabetic kidney. We demonstrate that diabetic mice devoid of the circadian transcriptional regulator BMAL1 in the renal tubule exhibit additional enhancement of renal gluconeogenesis, exacerbated hyperglycemia, increased glucosuria, polyuria and renal hypertrophy. Collectively, our results suggest that diabetic hyperglycemia can be worsened by dysfunction or misalignment of intrinsic renal circadian clocks.
2022-05-27 | GSE178319 | GEO
Project description:Excessive glucose production in the liver is a key factor in the hyperglycemia observed in diabetes mellitus type 2. It is generally agreed to result from an increase in hepatic gluconeogenesis. Considerable attention has been devoted to the transcriptional regulation of key gluconeogenic enzymes, but much less is known about the regulation of amino-acid catabolism, which generates gluconeogenic substrates. Here, we highlight a novel role of LKB1 in this regulation. We show that mice with a hepatocyte-specific deletion of Lkb1 have higher levels of hepatic amino acid catabolism, driving gluconeogenesis. This effect was observed during both fasting and the postprandial period, identifying Lkb1 as a critical suppressor of postprandial hepatic gluconeogenesis. Hepatic Lkb1 deletion was associated with major changes in whole-body metabolism, leading to a lower lean body mass and, in the longer term, sarcopenia and cachexia, as a consequence of the diversion of amino acids to liver metabolism at the expense of muscle. Using genetic and pharmacological approaches, we identified the aminotransferases and specifically, Agxt as effectors of the suppressor function of Lkb1 in amino acid-driven gluconeogenesis. The present dataset is from the phosphoproteomic analysis of fasting mice in a study where a global quantitative analysis ( PXD013478 ) is also described in the same publication.
2020-12-01 | PXD019757 | Pride
Project description:Excessive glucose production in the liver is a key factor in the hyperglycemia observed in diabetes mellitus type 2. It is generally agreed to result from an increase in hepatic gluconeogenesis. Considerable attention has been devoted to the transcriptional regulation of key gluconeogenic enzymes, but much less is known about the regulation of amino-acid catabolism, which generates gluconeogenic substrates. Here, we highlight a novel role of LKB1 in this regulation. We show that mice with a hepatocyte-specific deletion of Lkb1 have higher levels of hepatic amino acid catabolism, driving gluconeogenesis. This effect was observed during both fasting and the postprandial period, identifying Lkb1 as a critical suppressor of postprandial hepatic gluconeogenesis. Hepatic Lkb1 deletion was associated with major changes in whole-body metabolism, leading to a lower lean body mass and, in the longer term, sarcopenia and cachexia, as a consequence of the diversion of amino acids to liver metabolism at the expense of muscle. Using genetic and pharmacological approaches, we identified the aminotransferases and specifically, Agxt as effectors of the suppressor function of Lkb1 in amino acid-driven gluconeogenesis. The present dataset is from the phosphoproteomic analysis of the refed mice in a study where a global quantitative analysis ( PXD013478 ) is also described in the same publication.
2020-12-01 | PXD019755 | Pride
Project description:Excessive hepatic glucose production is a major contributor to the hyperglycemia observed in Type 2 diabetes mellitus. It is widely accepted that it is due to an increase in hepatic gluconeogenesis. While much attention has been devoted to the transcriptional regulation of key gluconeogenic enzymes, much less is known about the regulation of amino acid catabolism that provides gluconeogenic substrates. Here, we emphasize a novel role of LKB1 in this regulation. We show that mice with a hepatocyte-specific deletion of Lkb1 have increased hepatic amino acid catabolism for gluconeogenesis. This occurred during fasting, as well as during the postprandial period, identifying Lkb1 as a critical suppressor of hepatic postprandial gluconeogenesis. Hepatic Lkb1 deletion was also associated with severe alterations in whole body metabolism leading to decreased lean body mass deposition on MRI analysis and, at a longer term, cachexia and sarcopenia as a consequence of the diversion of amino acids for liver metabolism at the expense of muscle. Using genetic and pharmacological approaches, we identified the aminotransferases and Agxt and as critical effectors of the suppressor function of Lkb1 in amino acid-driven gluconeogenesis.
2020-12-01 | PXD013478 | Pride
Project description:A short sequence of 11 amino acids belonging to the cj0669 protein from Campylobacter jejuni NCTC 11168, which was previously identified as potentially immunogenic, was analyzed via alanine scanning to narrow down the significant amino acid residues within the sequence. Twelve peptides, one representing the original sequence and eleven peptides with each residue replaced by alanine in turn, were synthesized on microarrays by JPTs Pepstar Technology. For each microarray, nine replicates for each peptide were spotted. The microarray was separated into three incubation chambers by the ProPlate 3-well module (Grace Biolabs) to allow for incubation with different antibodies in parallel. For specific interactions, rabbit polyclonal IgG to C. jejuni was used, while unspecific binding to the epitope sequence was checked using rabbit polyclonal IgG to Salmonella enterica.
2013-04-06 | E-GEOD-45556 | biostudies-arrayexpress
Project description:A short sequence of 11 amino acids belonging to the cj0669 protein from Campylobacter jejuni NCTC 11168 which was previously identified as potentially immunogenig was analyzed via alanine scanning to narrow down the significant amino acid residues within the sequence. Twelve peptides, one representing the original sequence and eleven peptides with each residue replaced by alanine in turn, were synthesized on microarrays by JPTs Pepstar Technology. For each microarray, nine replicates for each peptide were spotted. The microarray was seperated into three incubation chambers by the ProPlate 3-well module (Grace Biolabs) to allow for incubation with different antibodies in parallel. For specific interaction rabbit polyclonal IgG to C.jejuni was used, while non-specific binding to the epitope sequence was checked using rabbit polyclonal IgG to H. pylori (Abcam ab20459).
2013-05-06 | E-GEOD-46651 | biostudies-arrayexpress