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Role of Essential Amino Acids in Age-Induced Bone Loss. Int J Mol Sci 2022; 23:ijms231911281. [PMID: 36232583 PMCID: PMC9569615 DOI: 10.3390/ijms231911281] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 09/16/2022] [Accepted: 09/20/2022] [Indexed: 11/16/2022] Open
Abstract
Age-induced osteoporosis is a global problem. Essential amino acids (EAAs) work as an energy source and a molecular pathway modulator in bone, but their functions have not been systematically reviewed in aging bone. This study aimed to discuss the contribution of EAAs on aging bone from in vitro, in vivo, and human investigations. In aged people with osteoporosis, serum EAAs were detected changing up and down, without a well-established conclusion. The supply of EAAs in aged people either rescued or did not affect bone mineral density (BMD) and bone volume. In most signaling studies, EAAs were proven to increase bone mass. Lysine, threonine, methionine, tryptophan, and isoleucine can increase osteoblast proliferation, activation, and differentiation, and decrease osteoclast activity. Oxidized L-tryptophan promotes bone marrow stem cells (BMSCs) differentiating into osteoblasts. However, the oxidation product of tryptophan called kynurenine increases osteoclast activity, and enhances the differentiation of adipocytes from BMSCs. Taken together, in terms of bone minerals and volume, more views consider EAAs to have a positive effect on aging bone, but the function of EAAs in bone metabolism has not been fully demonstrated and more studies are needed in this area in the future.
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Song X, Han L, Lin X, Tian M, Sun F, Feng B. Jian Pi Tiao Gan Yin alleviates obesity phenotypes through mTORC1/SREBP1 signaling in vitro and in vivo. ANNALS OF TRANSLATIONAL MEDICINE 2022; 10:291. [PMID: 35433951 PMCID: PMC9011225 DOI: 10.21037/atm-22-685] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 03/07/2022] [Indexed: 11/25/2022]
Abstract
Background Obesity has been considered as a leading cause of multiple metabolic syndromes, such as type 2 diabetes and hypertension cardiovascular diseases. Jian Pi Tiao Gan Yin (JPTGY), a Chinese herb preparation, is used to treat obesity of liver qi stagnation and spleen deficiency. The mechanism of action of JPTGY in obesity remains unclear. This study evaluated the effect of JPTGY on obesity. Methods The mechanism of action of JPTGY on obesity was investigated in high-fat diet (HFD)-induced obese mice and palmitic acid-treated 3T3-L1 cells. Lipid droplet accumulation was detected using oil red O staining. Factors associated with lipid accumulation were detected by western blotting. Results Treatment with JPTGY reduced HFD-induced adiposity and body weight gain. JPTGY increased the levels of brown adipose tissue biomarkers in obese mice and palmitic acid-treated 3T3-L1 cells, including peroxisome proliferator-activated receptor gamma coactivator-1-alpha (PGC-1α) and uncoupling protein-1 (UCP-1). Meanwhile, the protein expression of white adipose tissue biomarkers, such as AGT, primary subtalar arthrodesis (PSTA), and endothelin receptor type A (EDNRA), was decreased in obese mice and palmitic acid-treated 3T3-L1 cells. JPTGY affects browning of 3T3-L1 cells through mechanistic target of rapamycin complex 1 (mTORC1) signaling. JPTGY decreased the expression levels of key adipogenic-specific proteins and lipogenic enzymes, including peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer binding protein α (C/EBPα), sterol regulatory element binding protein (SREBP), and FAS. Treatment with the mTOR activator MHY reversed JPTGY-mediated protein expression. Conclusions We concluded that JPTGY relieved obesity phenotypes through mTORC1/SREBP1 signaling in vitro and in vivo. JPTGY may benefit the attenuation of obesity.
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Affiliation(s)
- Xiaoming Song
- Department of Geriatrics, the First Affiliated Hospital of Shandong First Medical University, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
| | - Lulu Han
- Neurology Ward 3, the Fifth People's Hospital of Jinan, Jinan, China
| | - Xiaowan Lin
- First Clinical Medical College, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Minghui Tian
- First Clinical Medical College, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Fenglei Sun
- General Medicine, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Bo Feng
- Department of Geriatrics, the First Affiliated Hospital of Shandong First Medical University, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
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Tangseefa P, Martin SK, Arthur A, Panagopoulos V, Page AJ, Wittert GA, Proud CG, Fitter S, Zannettino ACW. Deletion of Rptor in Preosteoblasts Reveals a Role for the Mammalian Target of Rapamycin Complex 1 (mTORC1) Complex in Dietary-Induced Changes to Bone Mass and Glucose Homeostasis in Female Mice. JBMR Plus 2021; 5:e10486. [PMID: 33977204 PMCID: PMC8101617 DOI: 10.1002/jbm4.10486] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 02/22/2021] [Accepted: 02/28/2021] [Indexed: 12/11/2022] Open
Abstract
The mammalian target of rapamycin complex 1 (mTORC1) complex is the major nutrient sensor in mammalian cells that responds to amino acids, energy levels, growth factors, and hormones, such as insulin, to control anabolic and catabolic processes. We have recently shown that suppression of the mTORC1 complex in bone‐forming osteoblasts (OBs) improved glucose handling in male mice fed a normal or obesogenic diet. Mechanistically, this occurs, at least in part, by increasing OB insulin sensitivity leading to upregulation of glucose uptake and glycolysis. Given previously reported sex‐dependent differences observed upon antagonism of mTORC1 signaling, we investigated the metabolic and skeletal effects of genetic inactivation of preosteoblastic‐mTORC1 in female mice. Eight‐week‐old control diet (CD)‐fed Rptorob−/− mice had a low bone mass with a significant reduction in trabecular bone volume and trabecular number, reduced cortical bone thickness, and increased marrow adiposity. Despite no changes in body composition, CD‐fed Rptorob−/− mice exhibited significant lower fasting insulin and glucose levels and increased insulin sensitivity. Upon high‐fat diet (HFD) feeding, Rptorob−/− mice were resistant to a diet‐induced increase in whole‐body and total fat mass and protected from the development of diet‐induced insulin resistance. Notably, although 12 weeks of HFD increased marrow adiposity, with minimal changes in both trabecular and cortical bone in the female control mice, marrow adiposity was significantly reduced in HFD‐fed Rptorob−/− compared to both HFD‐fed control and CD‐fed Rptorob−/− mice. Collectively, our results demonstrate that mTORC1 function in preosteoblasts is crucial for skeletal development and skeletal regulation of glucose homeostasis in both male and female mice. Importantly, loss of mTORC1 function in OBs results in metabolic and physiological adaptations that mirror a caloric restriction phenotype (under CD) and protects against HFD‐induced obesity, associated insulin resistance, and marrow adiposity expansion. These results highlight the critical contribution of the skeleton in the regulation of whole‐body energy homeostasis. © 2021 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.
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Affiliation(s)
- Pawanrat Tangseefa
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia
| | - Sally K Martin
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia
| | - Agnieszka Arthur
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia
| | - Vasilios Panagopoulos
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia
| | - Amanda J Page
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Nutrition, Diabetes & Gut Health Program, Lifelong Health Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia
| | - Gary A Wittert
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Nutrition, Diabetes & Gut Health Program, Lifelong Health Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia.,Freemasons Foundation Centre for Men's Health University of Adelaide Adelaide South Australia Australia
| | - Christopher G Proud
- Nutrition, Diabetes & Gut Health Program, Lifelong Health Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia.,School of Biological Sciences, University of Adelaide Adelaide South Australia Australia
| | - Stephen Fitter
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia
| | - Andrew C W Zannettino
- Adelaide Medical School, Faculty of Health and Medical Science University of Adelaide Adelaide South Australia Australia.,Cancer Program, Precision Medicine Theme, South Australian Health and Medical Research Institute Adelaide South Australia Australia.,Central Adelaide Local Health Network Adelaide South Australia Australia
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