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Metformin Improves Diabetic Bone Health by Re-Balancing Catabolism and Nitrogen Disposal.

Li X, Guo Y, Yan W, Snyder MP, Li X - PLoS ONE (2015)

Bottom Line: A total of 346 unique metabolites were identified, and they are grouped into distinctive clusters that reflected general and diabetes-specific responses to metformin.As evidenced by changes in the TCA and urea cycles, increased catabolism and nitrogen waste that are commonly associated with diabetes were rebalanced upon treatment with metformin.In particular, we found glutamate and succinate whose levels were drastically elevated in diabetic animals were brought back to normal levels by metformin.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, Stanford University, Stanford, CA 94305-5120, United States of America.

ABSTRACT

Objective: Metformin, a leading drug used to treat diabetic patients, is reported to benefit bone homeostasis under hyperglycemia in animal models. However, both the molecular targets and the biological pathways affected by metformin in bone are not well identified or characterized. The objective of this study is to investigate the bioengergeric pathways affected by metformin in bone marrow cells of mice.

Materials and methods: Metabolite levels were examined in bone marrow samples extracted from metformin or PBS -treated healthy (Wild type) and hyperglycemic (diabetic) mice using liquid chromatography-mass spectrometry (LC-MS)-based metabolomics. We applied an untargeted high performance LC-MS approach which combined multimode chromatography (ion exchange, reversed phase and hydrophilic interaction (HILIC)) and Orbitrap-based ultra-high accuracy mass spectrometry to achieve a wide coverage. A multivariate clustering was applied to reveal the global trends and major metabolite players.

Results: A total of 346 unique metabolites were identified, and they are grouped into distinctive clusters that reflected general and diabetes-specific responses to metformin. As evidenced by changes in the TCA and urea cycles, increased catabolism and nitrogen waste that are commonly associated with diabetes were rebalanced upon treatment with metformin. In particular, we found glutamate and succinate whose levels were drastically elevated in diabetic animals were brought back to normal levels by metformin. These two metabolites were further validated as the major targets of metformin in bone marrow stromal cells.

Conclusion: Overall using limited sample size, our study revealed the metabolic pathways modulated by metformin in bones which have broad implication in our understanding of bone remodeling under hyperglycemia and in finding therapeutic interventions in mammals.

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Related in: MedlinePlus

Metformin shifted metabolomics profiles of bone marrow in both wild-type and hyperglycemic mice.A. The clustering scatter plot of 345 metabolites from bone marrow cells of WT and MKR mice upon metformin (Met) or control (PBS) treatment. Each dot represents one of 3 technical replicates from each of 4 biological samples (for MKR_Met, n = 3). The clustering used the O2PLS-DA model and unit-variance scaling in SIMCA. R2Y = 0.942. Q2 = 0.591. B. The scatter plot of metabolite contribution to clustering in panel A. The first and second predictive components (R2 = 0.631) from the O2PLS-DA model in panel A. are superimposed with their p and q plots. Each magenta dot represents a metabolite. Each blue dot represents the reference point for each sample group. The names were showed for a few metabolites with high discriminatory power between sample groups. Plots were generated in SIMCA. C-D. The scatter plot of metabolite contribution in two representative KEGG metabolism pathways (as in Fig 2B). All metabolites in the displayed pathway are showed if detected in this study regardless of their statistical significance. Metformin is always included as reference.
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pone.0146152.g002: Metformin shifted metabolomics profiles of bone marrow in both wild-type and hyperglycemic mice.A. The clustering scatter plot of 345 metabolites from bone marrow cells of WT and MKR mice upon metformin (Met) or control (PBS) treatment. Each dot represents one of 3 technical replicates from each of 4 biological samples (for MKR_Met, n = 3). The clustering used the O2PLS-DA model and unit-variance scaling in SIMCA. R2Y = 0.942. Q2 = 0.591. B. The scatter plot of metabolite contribution to clustering in panel A. The first and second predictive components (R2 = 0.631) from the O2PLS-DA model in panel A. are superimposed with their p and q plots. Each magenta dot represents a metabolite. Each blue dot represents the reference point for each sample group. The names were showed for a few metabolites with high discriminatory power between sample groups. Plots were generated in SIMCA. C-D. The scatter plot of metabolite contribution in two representative KEGG metabolism pathways (as in Fig 2B). All metabolites in the displayed pathway are showed if detected in this study regardless of their statistical significance. Metformin is always included as reference.

Mentions: The KEGG IDs for all 65 metabolites with a high pq2 score (>0.05, see Fig 2B) were used for the pathway enrichment analysis (http://impala.molgen.mpg.de/impala/impala). The Q-value cut-off were < 0.01.


Metformin Improves Diabetic Bone Health by Re-Balancing Catabolism and Nitrogen Disposal.

Li X, Guo Y, Yan W, Snyder MP, Li X - PLoS ONE (2015)

Metformin shifted metabolomics profiles of bone marrow in both wild-type and hyperglycemic mice.A. The clustering scatter plot of 345 metabolites from bone marrow cells of WT and MKR mice upon metformin (Met) or control (PBS) treatment. Each dot represents one of 3 technical replicates from each of 4 biological samples (for MKR_Met, n = 3). The clustering used the O2PLS-DA model and unit-variance scaling in SIMCA. R2Y = 0.942. Q2 = 0.591. B. The scatter plot of metabolite contribution to clustering in panel A. The first and second predictive components (R2 = 0.631) from the O2PLS-DA model in panel A. are superimposed with their p and q plots. Each magenta dot represents a metabolite. Each blue dot represents the reference point for each sample group. The names were showed for a few metabolites with high discriminatory power between sample groups. Plots were generated in SIMCA. C-D. The scatter plot of metabolite contribution in two representative KEGG metabolism pathways (as in Fig 2B). All metabolites in the displayed pathway are showed if detected in this study regardless of their statistical significance. Metformin is always included as reference.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4696809&req=5

pone.0146152.g002: Metformin shifted metabolomics profiles of bone marrow in both wild-type and hyperglycemic mice.A. The clustering scatter plot of 345 metabolites from bone marrow cells of WT and MKR mice upon metformin (Met) or control (PBS) treatment. Each dot represents one of 3 technical replicates from each of 4 biological samples (for MKR_Met, n = 3). The clustering used the O2PLS-DA model and unit-variance scaling in SIMCA. R2Y = 0.942. Q2 = 0.591. B. The scatter plot of metabolite contribution to clustering in panel A. The first and second predictive components (R2 = 0.631) from the O2PLS-DA model in panel A. are superimposed with their p and q plots. Each magenta dot represents a metabolite. Each blue dot represents the reference point for each sample group. The names were showed for a few metabolites with high discriminatory power between sample groups. Plots were generated in SIMCA. C-D. The scatter plot of metabolite contribution in two representative KEGG metabolism pathways (as in Fig 2B). All metabolites in the displayed pathway are showed if detected in this study regardless of their statistical significance. Metformin is always included as reference.
Mentions: The KEGG IDs for all 65 metabolites with a high pq2 score (>0.05, see Fig 2B) were used for the pathway enrichment analysis (http://impala.molgen.mpg.de/impala/impala). The Q-value cut-off were < 0.01.

Bottom Line: A total of 346 unique metabolites were identified, and they are grouped into distinctive clusters that reflected general and diabetes-specific responses to metformin.As evidenced by changes in the TCA and urea cycles, increased catabolism and nitrogen waste that are commonly associated with diabetes were rebalanced upon treatment with metformin.In particular, we found glutamate and succinate whose levels were drastically elevated in diabetic animals were brought back to normal levels by metformin.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, Stanford University, Stanford, CA 94305-5120, United States of America.

ABSTRACT

Objective: Metformin, a leading drug used to treat diabetic patients, is reported to benefit bone homeostasis under hyperglycemia in animal models. However, both the molecular targets and the biological pathways affected by metformin in bone are not well identified or characterized. The objective of this study is to investigate the bioengergeric pathways affected by metformin in bone marrow cells of mice.

Materials and methods: Metabolite levels were examined in bone marrow samples extracted from metformin or PBS -treated healthy (Wild type) and hyperglycemic (diabetic) mice using liquid chromatography-mass spectrometry (LC-MS)-based metabolomics. We applied an untargeted high performance LC-MS approach which combined multimode chromatography (ion exchange, reversed phase and hydrophilic interaction (HILIC)) and Orbitrap-based ultra-high accuracy mass spectrometry to achieve a wide coverage. A multivariate clustering was applied to reveal the global trends and major metabolite players.

Results: A total of 346 unique metabolites were identified, and they are grouped into distinctive clusters that reflected general and diabetes-specific responses to metformin. As evidenced by changes in the TCA and urea cycles, increased catabolism and nitrogen waste that are commonly associated with diabetes were rebalanced upon treatment with metformin. In particular, we found glutamate and succinate whose levels were drastically elevated in diabetic animals were brought back to normal levels by metformin. These two metabolites were further validated as the major targets of metformin in bone marrow stromal cells.

Conclusion: Overall using limited sample size, our study revealed the metabolic pathways modulated by metformin in bones which have broad implication in our understanding of bone remodeling under hyperglycemia and in finding therapeutic interventions in mammals.

Show MeSH
Related in: MedlinePlus