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Article

mTORC1 and mTORC2 Complexes Regulate the Untargeted Metabolomics and Amino Acid Metabolites Profile through Mitochondrial Bioenergetic Functions in Pancreatic Beta Cells

1
Department of Environmental, Occupational, and Geospatial Health Sciences, Graduate School of Public Health and Health Policy, City University of New York, New York, NY 10027, USA
2
Structural Biology Initiative, Advanced Science Research Center (ASRC), City University of New York, New York, NY 10031, USA
3
Neuroscience Initiative, Advanced Science Research Center (ASRC), City University of New York, 85 St. Nicholas Terrace, New York, NY 10031, USA
*
Author to whom correspondence should be addressed.
Academic Editor: Roberto Iacone
Nutrients 2022, 14(15), 3022; https://doi.org/10.3390/nu14153022
Received: 19 June 2022 / Revised: 15 July 2022 / Accepted: 18 July 2022 / Published: 22 July 2022
(This article belongs to the Section Nutrition and Metabolism)
Background: Pancreatic beta cells regulate bioenergetics efficiency and secret insulin in response to glucose and nutrient availability. The mechanistic Target of Rapamycin (mTOR) network orchestrates pancreatic progenitor cell growth and metabolism by nucleating two complexes, mTORC1 and mTORC2. Objective: To determine the impact of mTORC1/mTORC2 inhibition on amino acid metabolism in mouse pancreatic beta cells (Beta-TC-6 cells, ATCC-CRL-11506) using high-resolution metabolomics (HRM) and live-mitochondrial functions. Methods: Pancreatic beta TC-6 cells were incubated for 24 h with either: RapaLink-1 (RL); Torin-2 (T); rapamycin (R); metformin (M); a combination of RapaLink-1 and metformin (RLM); Torin-2 and metformin (TM); compared to the control. We applied high-resolution mass spectrometry (HRMS) LC-MS/MS untargeted metabolomics to compare the twenty natural amino acid profiles to the control. In addition, we quantified the bioenergetics dynamics and cellular metabolism by live-cell imaging and the MitoStress Test XF24 (Agilent, Seahorse). The real-time, live-cell approach simultaneously measures the oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) to determine cellular respiration and metabolism. Statistical significance was assessed using ANOVA on Ranks and post-hoc Welch t-Tests. Results: RapaLink-1, Torin-2, and rapamycin decreased L-aspartate levels compared to the control (p = 0.006). Metformin alone did not affect L-aspartate levels. However, L-asparagine levels decreased with all treatment groups compared to the control (p = 0.03). On the contrary, L-glutamate and glycine levels were reduced only by mTORC1/mTORC2 inhibitors RapaLink-1 and Torin-2, but not by rapamycin or metformin. The metabolic activity network model predicted that L-aspartate and AMP interact within the same activity network. Live-cell bioenergetics revealed that ATP production was significantly reduced in RapaLink-1 (122.23 ± 33.19), Torin-2 (72.37 ± 17.33) treated cells, compared to rapamycin (250.45 ± 9.41) and the vehicle control (274.23 ± 38.17), p < 0.01. However, non-mitochondrial oxygen consumption was not statistically different between RapaLink-1 (67.17 ± 3.52), Torin-2 (55.93 ± 8.76), or rapamycin (80.01 ± 4.36, p = 0.006). Conclusions: Dual mTORC1/mTORC2 inhibition by RapaLink-1 and Torin-2 differentially altered the amino acid profile and decreased mitochondrial respiration compared to rapamycin treatment which only blocks the FRB domain on mTOR. Third-generation mTOR inhibitors may alter the mitochondrial dynamics and reveal a bioenergetics profile that could be targeted to reduce mitochondrial stress. View Full-Text
Keywords: mTORC1; mTORC2; high-resolution mass spectrometry (HRMS); mitochondrial stress; oxygen consumption rate (OCR); extra cellular acidification rate (ECAR); the internal exposome mTORC1; mTORC2; high-resolution mass spectrometry (HRMS); mitochondrial stress; oxygen consumption rate (OCR); extra cellular acidification rate (ECAR); the internal exposome
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MDPI and ACS Style

Soliman, G.A.; Abzalimov, R.R.; He, Y. mTORC1 and mTORC2 Complexes Regulate the Untargeted Metabolomics and Amino Acid Metabolites Profile through Mitochondrial Bioenergetic Functions in Pancreatic Beta Cells. Nutrients 2022, 14, 3022. https://doi.org/10.3390/nu14153022

AMA Style

Soliman GA, Abzalimov RR, He Y. mTORC1 and mTORC2 Complexes Regulate the Untargeted Metabolomics and Amino Acid Metabolites Profile through Mitochondrial Bioenergetic Functions in Pancreatic Beta Cells. Nutrients. 2022; 14(15):3022. https://doi.org/10.3390/nu14153022

Chicago/Turabian Style

Soliman, Ghada A., Rinat R. Abzalimov, and Ye He. 2022. "mTORC1 and mTORC2 Complexes Regulate the Untargeted Metabolomics and Amino Acid Metabolites Profile through Mitochondrial Bioenergetic Functions in Pancreatic Beta Cells" Nutrients 14, no. 15: 3022. https://doi.org/10.3390/nu14153022

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