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Hou X, Song S, Xu Z, Shi Y, Yang Y, Zhang L, Cui Y, Wang C, Lin Y. Prolactin upregulates amino acids uptake in dairy cow mammary epithelial cells via LAT1. J Dairy Sci 2024:S0022-0302(24)00966-4. [PMID: 38945262 DOI: 10.3168/jds.2024-24746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2024] [Accepted: 06/02/2024] [Indexed: 07/02/2024]
Abstract
The uptake of AA in mammary tissues is affected by prolactin (PRL). To investigate whether PRL-induced AA uptake is involved in L-type AA transporter 1 (LAT1), we analyzed the changes of AA in the medium of dairy cow mammary epithelial cells in the presence of PRL or PRL plus BCH, an inhibitor of LAT1. Then Western blot and luciferase assay were used to detect the regulation mechanism of PRL on LAT1 expression and function. Our results showed that Thr, Val, Met, Ile, Leu, Tyr, Lys, Phe, and His are LAT1 substrates and could be transported into mammary epithelial cells via LAT1. PRL stimulation increased the uptake of most AA into mammary epithelial cells of dairy cows, however, inhibition of LAT1 transport activity reduced PRL-induced AA uptake, suggesting that the effect of PRL on AA transport depends on LAT1 expression and function. PRL stimulation upregulated LAT1 expression and plasma membrane location not only in dairy cow mammary epithelial cells, but also in mouse mammary epithelial cell line HC11. Western blot showed that PI3K-AKT-mTOR signaling could be activated in PRL-stimulated mammary epithelial cells. Treatment of cells with LY294002 decreased PI3K-AKT-mTOR activation, as well LAT1 expression, that in turn decreased milk protein synthesis. Luciferase assay showed PRL treatment increased the promoter activity of LAT1 promoter fragment -419∼-86 bp. Treatment of cells with LY294002, an inhibitor of PI3K, or SC79, an activator of AKT abolished or promoted the transcriptional activity of this promoter fragment in the presence of PRL. These results suggested that the -419∼-86 bp fragment of LAT1 promoter mediates the action of PI3K-AKT-mTOR signaling on LAT1 transcription in mammary epithelial cells of dairy cows, which in turn increased LAT1 expression and AA uptake.
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Affiliation(s)
- Xiaoming Hou
- Key Laboratory of Animal Cellular and Genetics Engineering of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
| | - Shuyuan Song
- Key Laboratory of Animal Cellular and Genetics Engineering of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
| | - Ziru Xu
- Key Laboratory of Animal Cellular and Genetics Engineering of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
| | - Ying Shi
- Key Laboratory of Animal Cellular and Genetics Engineering of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
| | - Yang Yang
- Key Laboratory of Animal Cellular and Genetics Engineering of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China
| | - Li Zhang
- Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin 150030, China
| | - Yingjun Cui
- Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin 150030, China
| | - Chunmei Wang
- Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin 150030, China
| | - Ye Lin
- Key Laboratory of Animal Cellular and Genetics Engineering of Heilongjiang Province, Northeast Agricultural University, Harbin 150030, China; Key Laboratory of Dairy Science of Education Ministry, Northeast Agricultural University, Harbin 150030, China.
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Ramshankar G, Liu R, Perry RJ. The association between the amino acid transporter LAT1, tumor immunometabolic and proliferative features and menopausal status in breast cancer. PLoS One 2023; 18:e0292678. [PMID: 37819900 PMCID: PMC10566702 DOI: 10.1371/journal.pone.0292678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 09/26/2023] [Indexed: 10/13/2023] Open
Abstract
L-type Amino Acid Transporter 1 (LAT1) facilitates the uptake of specific essential amino acids, and due to this quality, it has been correlated to worse patient outcomes in various cancer types. However, the relationship between LAT1 and various clinical factors, including menopausal status, in mediating LAT1's prognostic effects remains incompletely understood. This is particularly true in the unique subset of tumors that are both obesity-associated and responsive to immunotherapy, including breast cancer. To close this gap, we employed 6 sets of transcriptomic data using the Kaplan-Meier model in the Xena Functional Genomics Explorer, demonstrating that higher LAT1 expression diminishes breast cancer patients' survival probability. Additionally, we analyzed 3'-Deoxy-3'-18F-Fluorothymidine positron emission tomography-computed tomography (18F-FLT PET-CT) images found on The Cancer Imaging Archive (TCIA). After separating all patients based on menopausal status, we correlated the measured 18F-FLT uptake with various clinical parameters quantifying body composition, tumor proliferation, and immune cell infiltration. By analyzing a wealth of deidentified, open-access data, the current study investigates the impact of LAT1 expression on breast cancer prognosis, along with the menopausal status-dependent associations between tumor proliferation, immunometabolism, and systemic metabolism.
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Affiliation(s)
- Gautham Ramshankar
- Irvington High School, Fremont, California, United States of America
- Departments of Cellular & Molecular Physiology and Internal Medicine (Endocrinology), Yale School of Medicine, New Haven, Connecticut, United States of America
| | - Ryan Liu
- Departments of Cellular & Molecular Physiology and Internal Medicine (Endocrinology), Yale School of Medicine, New Haven, Connecticut, United States of America
- Cedar Park High School, Cedar Park, Texas, United States of America
| | - Rachel J. Perry
- Departments of Cellular & Molecular Physiology and Internal Medicine (Endocrinology), Yale School of Medicine, New Haven, Connecticut, United States of America
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Collao N, D'Souza D, Messeiller L, Pilon E, Lloyd J, Larkin J, Ngu M, Cuillerier A, Green AE, Menzies KJ, Burelle Y, De Lisio M. Radiation induces long-term muscle fibrosis and promotes a fibrotic phenotype in fibro-adipogenic progenitors. J Cachexia Sarcopenia Muscle 2023; 14:2335-2349. [PMID: 37671686 PMCID: PMC10570115 DOI: 10.1002/jcsm.13320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/29/2023] [Accepted: 07/24/2023] [Indexed: 09/07/2023] Open
Abstract
BACKGROUND Radiation-induced muscle pathology, characterized by muscle atrophy and fibrotic tissue accumulation, is the most common debilitating late effect of therapeutic radiation exposure particularly in juvenile cancer survivors. In healthy muscle, fibro/adipogenic progenitors (FAPs) are required for muscle maintenance and regeneration, while in muscle pathology FAPs are precursors for exacerbated extracellular matrix deposition. However, the role of FAPs in radiation-induced muscle pathology has not previously been explored. METHODS Four-week-old Male CBA or C57Bl/6J mice received a single dose (16 Gy) of irradiation (IR) to a single hindlimb with the shielded contralateral limb (CLTR) serving as a non-IR control. Mice were sacrificed 3, 7, 14 (acute IR response), and 56 days post-IR (long-term IR response). Changes in skeletal muscle morphology, myofibre composition, muscle niche cellular dynamics, DNA damage, proliferation, mitochondrial respiration, and metabolism and changes in progenitor cell fate where assessed. RESULTS Juvenile radiation exposure resulted in smaller myofibre cross-sectional area, particularly in type I and IIA myofibres (P < 0.05) and reduced the proportion of type I myofibres (P < 0.05). Skeletal muscle fibrosis (P < 0.05) was evident at 56 days post-IR. The IR-limb had fewer endothelial cells (P < 0.05) and fibro-adipogenic progenitors (FAPs) (P < 0.05) at 56 days post-IR. Fewer muscle satellite (stem) cells were detected at 3 and 56 days in the IR-limb (P < 0.05). IR induced FAP senescence (P < 0.05), increased their fibrogenic differentiation (P < 0.01), and promoted their glycolytic metabolism. Further, IR altered the FAP secretome in a manner that impaired muscle satellite (stem) cell differentiation (P < 0.05) and fusion (P < 0.05). CONCLUSIONS Our study suggests that following juvenile radiation exposure, FAPs contribute to long-term skeletal muscle atrophy and fibrosis. These findings provide rationale for investigating FAP-targeted therapies to ameliorate the negative late effects of radiation exposure in skeletal muscle.
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Affiliation(s)
- Nicolas Collao
- School of Human Kinetics, Faculty of Health ScienceUniversity of OttawaOttawaCanada
- Éric Poulin Centre for Neuromuscular DiseaseUniversity of OttawaOttawaCanada
| | - Donna D'Souza
- School of Human Kinetics, Faculty of Health ScienceUniversity of OttawaOttawaCanada
| | - Laura Messeiller
- School of Human Kinetics, Faculty of Health ScienceUniversity of OttawaOttawaCanada
| | - Evan Pilon
- School of Human Kinetics, Faculty of Health ScienceUniversity of OttawaOttawaCanada
| | - Jessica Lloyd
- School of Human Kinetics, Faculty of Health ScienceUniversity of OttawaOttawaCanada
| | - Jillian Larkin
- School of Human Kinetics, Faculty of Health ScienceUniversity of OttawaOttawaCanada
| | - Matthew Ngu
- School of Human Kinetics, Faculty of Health ScienceUniversity of OttawaOttawaCanada
| | - Alexanne Cuillerier
- Interdisciplinary School of Health SciencesUniversity of OttawaOttawaCanada
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems BiologyUniversity of OttawaOttawaCanada
| | - Alexander E. Green
- Éric Poulin Centre for Neuromuscular DiseaseUniversity of OttawaOttawaCanada
- Interdisciplinary School of Health SciencesUniversity of OttawaOttawaCanada
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems BiologyUniversity of OttawaOttawaCanada
| | - Keir J. Menzies
- Éric Poulin Centre for Neuromuscular DiseaseUniversity of OttawaOttawaCanada
- Interdisciplinary School of Health SciencesUniversity of OttawaOttawaCanada
- Department of Biochemistry, Microbiology and Immunology, Ottawa Institute of Systems BiologyUniversity of OttawaOttawaCanada
| | - Yan Burelle
- Interdisciplinary School of Health SciencesUniversity of OttawaOttawaCanada
| | - Michael De Lisio
- School of Human Kinetics, Faculty of Health ScienceUniversity of OttawaOttawaCanada
- Éric Poulin Centre for Neuromuscular DiseaseUniversity of OttawaOttawaCanada
- Department of Cellular and Molecular Medicine, Regenerative Medicine ProgramUniversity of OttawaOttawaCanada
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Rivera CN, Smith CE, Draper LV, Ochoa GE, Watne RM, Wommack AJ, Vaughan RA. The Selective LAT1 Inhibitor JPH203 Enhances Mitochondrial Metabolism and Content in Insulin-Sensitive and Insulin-Resistant C2C12 Myotubes. Metabolites 2023; 13:766. [PMID: 37367923 DOI: 10.3390/metabo13060766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 06/09/2023] [Accepted: 06/13/2023] [Indexed: 06/28/2023] Open
Abstract
Population data have shown an association between higher circulating branched-chain amino acids (BCAA) and the severity of insulin resistance in people with diabetes. While several studies have assessed BCAA metabolism as a potential target for regulation, less attention has been paid to the role of L-type amino acid transporter 1 (LAT1), the primary transporter of BCAA in skeletal muscle. The aim of this study was to assess the impact of JPH203 (JPH), a LAT1 inhibitor, on myotube metabolism in both insulin-sensitive and insulin-resistant myotubes. C2C12 myotubes were treated with or without 1 μM or 2 μM JPH for 24 h with or without insulin resistance. Western blot and qRT-PCR were used to assess protein content and gene expression, respectively. Mitochondrial and glycolytic metabolism were measured via Seahorse Assay, and fluorescent staining was used to measure mitochondrial content. BCAA media content was quantified using liquid chromatography-mass spectrometry. JPH at 1 μM (but not 2 μM) increased mitochondrial metabolism and content without inducing changes in mRNA expression of transcripts associated with mitochondrial biogenesis or mitochondrial dynamics. Along with increased mitochondrial function, 1μM treatment also reduced extracellular leucine and valine. JPH at 2 μM reduced pAkt signaling and increased extracellular accumulation of isoleucine without inducing changes in BCAA metabolic genes. Collectively, JPH may increase mitochondrial function independent of the mitochondrial biogenic transcription pathway; however, high doses may reduce insulin signaling.
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Affiliation(s)
- Caroline N Rivera
- Department of Exercise Science, High Point University, High Point, NC 27268, USA
| | - Carly E Smith
- Department of Exercise Science, High Point University, High Point, NC 27268, USA
| | - Lillian V Draper
- Department of Exercise Science, High Point University, High Point, NC 27268, USA
| | - Gabriela E Ochoa
- Department of Exercise Science, High Point University, High Point, NC 27268, USA
| | - Rachel M Watne
- Department of Chemistry, High Point University, High Point, NC 27268, USA
| | - Andrew J Wommack
- Department of Chemistry, High Point University, High Point, NC 27268, USA
| | - Roger A Vaughan
- Department of Exercise Science, High Point University, High Point, NC 27268, USA
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Rivera CN, Hinkle JS, Watne RM, Macgowan TC, Wommack AJ, Vaughan RA. PPAR β/ δ Agonism with GW501516 Increases Myotube PGC-1 α Content and Reduces BCAA Media Content Independent of Changes in BCAA Catabolic Enzyme Expression. PPAR Res 2023; 2023:4779199. [PMID: 37325367 PMCID: PMC10264138 DOI: 10.1155/2023/4779199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 05/01/2023] [Accepted: 05/17/2023] [Indexed: 06/17/2023] Open
Abstract
Background Type 2 diabetes is characterized by reduced insulin sensitivity, elevated blood metabolites, and reduced mitochondrial metabolism with reduced expression of genes governing metabolism such as peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PGC-1α). PGC-1α regulates the expression of branched-chain amino acid (BCAA) metabolism, and thus, increased circulating BCAA in diabetics may be partially explained by reduced PGC-1α expression. PGC-1α functions in-part through interactions with peroxisome proliferator-activated receptor β/δ (PPARβ/δ). The present report examined the effects of the PPARβ/δ agonism on cell metabolism and related gene/protein expression of cultured myotubes, with a primary emphasis on determining the effects of GW on BCAA disposal and catabolic enzyme expression. Methods C2C12 myotubes were treated with GW501516 (GW) for up to 24 hours. Mitochondrial and glycolytic metabolism were measured via oxygen consumption and extracellular acidification rate, respectively. Metabolic gene and protein expression were assessed via quantitative real-time polymerase chain reaction (qRT-PCR) and western blot, respectively. Media BCAA content was assessed via liquid chromatography-mass spectrometry (LC/MS). Results GW significantly increased PGC-1α protein expression, mitochondrial content, and mitochondrial function. GW also significantly reduced BCAA content within culture media following 24-hour treatment; however, expression of BCAA catabolic enzymes/transporter was unchanged. Conclusion These data confirm the ability of GW to increase muscle PGC-1α content and decrease BCAA media content without affecting BCAA catabolic enzymes/transporter. These findings suggest heightened BCAA uptake (and possibly metabolism) may occur without substantial changes in the protein levels of related cell machinery.
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Affiliation(s)
- Caroline N. Rivera
- Department of Exercise Science, High Point University, High Point, NC, USA
| | - Jason S. Hinkle
- Department of Exercise Science, High Point University, High Point, NC, USA
| | - Rachel M. Watne
- Department of Chemistry, High Point University, High Point, NC, USA
| | | | | | - Roger A. Vaughan
- Department of Exercise Science, High Point University, High Point, NC, USA
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Rivera CN, Kamer MM, Rivera ME, Watne RM, Macgowan TC, Wommack AJ, Vaughan RA. Insulin resistance promotes extracellular BCAA accumulation without altering LAT1 content, independent of prior BCAA treatment in a myotube model of skeletal muscle. Mol Cell Endocrinol 2023; 559:111800. [PMID: 36270542 DOI: 10.1016/j.mce.2022.111800] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2022] [Revised: 10/13/2022] [Accepted: 10/14/2022] [Indexed: 11/17/2022]
Abstract
PURPOSE Type 2 diabetes is characterized by reduced insulin sensitivity which correlates with increased circulating BCAA. These experiments investigated the effects of insulin resistance with and without excess BCAA on myotube insulin sensitivity and L-type amino acid transporter-1 (LAT1). METHODS C2C12 myotubes were treated with or without excess BCAA for 1 or 6 days, both with and without insulin resistance. Western blot was used to assess insulin sensitivity and LAT1 content. Liquid chromatography-mass spectrometry was used to evaluate BCAA media content. RESULTS Insulin resistance was associated with significantly increased extracellular BCAA accumulation independent of LAT1 content. Conversely, prior BCAA treatment was not associated with extracellular BCAA accumulation regardless of level of insulin sensitivity. CONCLUSION These data suggest insulin resistance, but not BCAA treatment, promotes extracellular BCAA accumulation independent of changes in LAT1 content, implicating insulin resistance as a causal agent of extracellular BCAA accumulation.
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Affiliation(s)
- Caroline N Rivera
- Department of Exercise Science, High Point University, High Point, NC, USA.
| | - Madison M Kamer
- Department of Exercise Science, High Point University, High Point, NC, USA.
| | - Madison E Rivera
- Department of Exercise Science, High Point University, High Point, NC, USA.
| | - Rachel M Watne
- Department of Chemistry, High Point University, High Point, NC, USA.
| | - Trent C Macgowan
- Department of Chemistry, High Point University, High Point, NC, USA.
| | - Andrew J Wommack
- Department of Chemistry, High Point University, High Point, NC, USA.
| | - Roger A Vaughan
- Department of Exercise Science, High Point University, High Point, NC, USA.
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Tinline-Goodfellow CT, Lees MJ, Hodson N. The skeletal muscle fiber periphery: A nexus of mTOR-related anabolism. SPORTS MEDICINE AND HEALTH SCIENCE 2022; 5:10-19. [PMID: 36994172 PMCID: PMC10040390 DOI: 10.1016/j.smhs.2022.11.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 11/16/2022] [Accepted: 11/23/2022] [Indexed: 12/02/2022] Open
Abstract
Skeletal muscle anabolism is driven by numerous stimuli such as growth factors, nutrients (i.e., amino acids, glucose), and mechanical stress. These stimuli are integrated by the mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) signal transduction cascade. In recent years, work from our laboratory and elsewhere has sought to unravel the molecular mechanisms underpinning the mTOR-related activation of muscle protein synthesis (MPS), as well as the spatial regulation of these mechanisms within the skeletal muscle cell. These studies have suggested that the skeletal muscle fiber periphery is a region of central importance in anabolism (i.e., growth/MPS). Indeed, the fiber periphery is replete with the substrates, molecular machinery, and translational apparatus necessary to facilitate MPS. This review provides a summary of the mechanisms underpinning the mTOR-associated activation of MPS from cell, rodent, and human studies. It also presents an overview of the spatial regulation of mTORC1 in response to anabolic stimuli and outlines the factors that distinguish the periphery of the cell as a highly notable region of skeletal muscle for the induction of MPS. Future research should seek to further explore the nutrient-induced activation of mTORC1 at the periphery of skeletal muscle fibers.
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Affiliation(s)
| | - Matthew J. Lees
- Faculty of Kinesiology and Physical Education, University of Toronto, Canada
| | - Nathan Hodson
- Faculty of Kinesiology and Physical Education, University of Toronto, Canada
- Institute of Sport, Manchester Metropolitan University, Manchester, United Kingdom
- Department of Sport and Exercise Sciences, Manchester Metropolitan University, Manchester, United Kingdom
- Corresponding author. Faculty of Kinesiology and Physical Education, University of Toronto, Canada.
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