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Deans-Fielder K, Wu T, Nguyen T, To S, Huang YZ, Bark SJ, Mills JC, Shroyer NF. Mechanisms driving fasting-induced protection from genotoxic injury in the small intestine. Am J Physiol Gastrointest Liver Physiol 2024; 326:G504-G524. [PMID: 38349111 DOI: 10.1152/ajpgi.00126.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 01/18/2024] [Accepted: 01/28/2024] [Indexed: 04/05/2024]
Abstract
Genotoxic agents such as doxorubicin (DXR) can cause damage to the intestines that can be ameliorated by fasting. How fasting is protective and the optimal timing of fasting and refeeding remain unclear. Here, our analysis of fasting/refeeding-induced global intestinal transcriptional changes revealed metabolic shifts and implicated the cellular energetic hub mechanistic target of rapamycin complex 1 (mTORC1) in protecting from DXR-induced DNA damage. Our analysis of specific transcripts and proteins in intestinal tissue and tissue extracts showed that fasting followed by refeeding at the time of DXR administration reduced damage and caused a spike in mTORC1 activity. However, continued fasting after DXR prevented the mTORC1 spike and damage reduction. Surprisingly, the mTORC1 inhibitor, rapamycin, did not block fasting/refeeding-induced reduction in DNA damage, suggesting that increased mTORC1 is dispensable for protection against the initial DNA damage response. In Ddit4-/- mice [DDIT4 (DNA-damage-inducible transcript 4) functions to regulate mTORC1 activity], fasting reduced DNA damage and increased intestinal crypt viability vs. ad libitum-fed Ddit4-/- mice. Fasted/refed Ddit4-/- mice maintained body weight, with increased crypt proliferation by 5 days post-DXR, whereas ad libitum-fed Ddit4-/- mice continued to lose weight and displayed limited crypt proliferation. Genes encoding epithelial stem cell and DNA repair proteins were elevated in DXR-injured, fasted vs. ad libitum Ddit4-/- intestines. Thus, fasting strongly reduced intestinal damage when normal dynamic regulation of mTORC1 was lost. Overall, the results confirm that fasting protects the intestines against DXR and suggests that fasting works by pleiotropic - including both mTORC1-dependent and independent - mechanisms across the temporally dynamic injury response.NEW & NOTEWORTHY New findings are 1) DNA damage reduction following a 24-h fast depends on the timing of postfast refeeding in relation to chemotherapy initiation; 2) fasting/refeeding-induced upregulation of mTORC1 activity is not required for early (6 h) protection against DXR-induced DNA damage; and 3) fasting increases expression of intestinal stem cell and DNA damage repair genes, even when mTORC1 is dysregulated, highlighting fasting's crucial role in regulating mTORC1-dependent and independent mechanisms in the dynamic recovery process.
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Affiliation(s)
- Kali Deans-Fielder
- Division of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, Houston, Texas, United States
- Translational Biology and Molecular Medicine Graduate Program, Graduate School of Biomedical Sciences, Baylor College of Medicine, Houston, Texas, United States
- Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas, United States
| | - Timothy Wu
- Medical Scientist Training Program, Baylor College of Medicine, Houston, Texas, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States
| | - Thanh Nguyen
- Division of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, Houston, Texas, United States
- Cancer and Cell Biology Graduate Program, Graduate School of Biomedical Sciences, Baylor College of Medicine, Houston, Texas, United States
| | - Sarah To
- Division of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, Houston, Texas, United States
| | - Yang-Zhe Huang
- Division of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, Houston, Texas, United States
- Cancer and Cell Biology Graduate Program, Graduate School of Biomedical Sciences, Baylor College of Medicine, Houston, Texas, United States
| | - Steven J Bark
- Division of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, Houston, Texas, United States
| | - Jason C Mills
- Division of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, Houston, Texas, United States
- Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas, United States
- Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States
| | - Noah F Shroyer
- Division of Gastroenterology and Hepatology, Department of Medicine, Baylor College of Medicine, Houston, Texas, United States
- Translational Biology and Molecular Medicine Graduate Program, Graduate School of Biomedical Sciences, Baylor College of Medicine, Houston, Texas, United States
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States
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2
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Michalski C, Cheung C, Oh JH, Ackermann E, Popescu CR, Archambault AS, Prusinkiewicz MA, Da Silva R, Majdoubi A, Viñeta Paramo M, Xu RY, Reicherz F, Patterson AE, Golding L, Sharma AA, Lim CJ, Orban PC, Klein Geltink RI, Lavoie PM. DDIT4L regulates mitochondrial and innate immune activities in early life. JCI Insight 2024; 9:e172312. [PMID: 38319716 PMCID: PMC11143921 DOI: 10.1172/jci.insight.172312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 01/31/2024] [Indexed: 02/07/2024] Open
Abstract
Pattern recognition receptor responses are profoundly attenuated before the third trimester of gestation in the relatively low-oxygen human fetal environment. However, the mechanisms regulating these responses are uncharacterized. Herein, genome-wide transcription and functional metabolic experiments in primary neonatal monocytes linked the negative mTOR regulator DDIT4L to metabolic stress, cellular bioenergetics, and innate immune activity. Using genetically engineered monocytic U937 cells, we confirmed that DDIT4L overexpression altered mitochondrial dynamics, suppressing their activity, and blunted LPS-induced cytokine responses. We also showed that monocyte mitochondrial function is more restrictive in earlier gestation, resembling the phenotype of DDIT4L-overexpressing U937 cells. Gene expression analyses in neonatal granulocytes and lung macrophages in preterm infants confirmed upregulation of the DDIT4L gene in the early postnatal period and also suggested a potential protective role against inflammation-associated chronic neonatal lung disease. Taken together, these data show that DDIT4L regulates mitochondrial activity and provide what we believe to be the first direct evidence for its potential role supressing innate immune activity in myeloid cells during development.
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Affiliation(s)
- Christina Michalski
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pediatrics and
| | - Claire Cheung
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pediatrics and
| | - Ju Hee Oh
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Emma Ackermann
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Constantin R. Popescu
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pediatrics and
- Department of Pediatrics, Université Laval, Quebec, Quebec, Canada
| | - Anne-Sophie Archambault
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Martin A. Prusinkiewicz
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pediatrics and
| | - Rachel Da Silva
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
| | - Abdelilah Majdoubi
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pediatrics and
| | - Marina Viñeta Paramo
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Women+ and Children′s Health, Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Rui Yang Xu
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Women+ and Children′s Health, Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Frederic Reicherz
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pediatrics and
| | - Annette E. Patterson
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Liam Golding
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pediatrics and
- Women+ and Children′s Health, Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ashish A. Sharma
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia, USA
| | - Chinten J. Lim
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pediatrics and
| | - Paul C. Orban
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Surgery, University of British Columbia, Vancouver, British Columbia, Canada
| | - Ramon I. Klein Geltink
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Pascal M. Lavoie
- British Columbia Children’s Hospital Research Institute, Vancouver, British Columbia, Canada
- Department of Pediatrics and
- Women+ and Children′s Health, Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, British Columbia, Canada
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3
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Chen X, Li Z, Liang M, Zhang Z, Zhu D, Lin B, Zhou R, Lu Y. Identification of DDIT4 as a potential prognostic marker associated with chemotherapeutic and immunotherapeutic response in triple-negative breast cancer. World J Surg Oncol 2023; 21:194. [PMID: 37391802 DOI: 10.1186/s12957-023-03078-7] [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: 10/17/2022] [Accepted: 06/14/2023] [Indexed: 07/02/2023] Open
Abstract
BACKGROUND Triple-negative breast cancer (TNBC) is the most heterogenous and aggressive subtype of breast cancer. Chemotherapy remains the standard treatment option for patients with TNBC owing to the unavailability of acceptable targets and biomarkers in clinical practice. Novel biomarkers and targets for patient stratification and treatment of TNBC are urgently needed. It has been reported that the overexpression of DNA damage-inducible transcript 4 gene (DDIT4) is associated with resistance to neoadjuvant chemotherapy and poor prognosis in patients with TNBC. In this study, we aimed to identify novel biomarkers and therapeutic targets using RNA sequencing (RNA-seq) and data mining using data from public databases. METHODS RNA sequencing (RNA-Seq) was performed to detect the different gene expression patterns in the human TNBC cell line HS578T treated with docetaxel or doxorubicin. Sequencing data were further analyzed by the R package "edgeR" and "clusterProfiler" to identify the profile of differentially expressed genes (DEGs) and annotate gene functions. The prognostic and predictive value of DDIT4 expression in patients with TNBC was further validated by published online data resources, including TIMER, UALCAN, Kaplan-Meier plotter, and LinkedOmics, and GeneMANIA and GSCALite were used to investigate the functional networks and hub genes related to DDIT4, respectively. RESULTS Through the integrative analyses of RNA-Seq data and public datasets, we observed the overexpression of DDIT4 in TNBC tissues and found that patients with DDIT4 overexpression showed poor survival outcomes. Notably, immune infiltration analysis showed that the levels of DDIT4 expression correlated negatively with the abundance of tumor-infiltrating immune cells and immune biomarker expression, but correlated positively with immune checkpoint molecules. Furthermore, DDIT4 and its hub genes (ADM, ENO1, PLOD1, and CEBPB) involved in the activation of apoptosis, cell cycle, and EMT pathways. Eventually, we found ADM, ENO1, PLOD1, and CEBPB showed poor overall survival in BC patients. CONCLUSION In this study, we found that DDIT4 expression is associated with the progression, therapeutic efficacy, and immune microenvironment of patients with TNBC, and DDIT4 would be as a potential prognostic biomarker and therapeutic target. These findings will help to identify potential molecular targets and improve therapeutic strategies against TNBC.
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Affiliation(s)
- Xuanzhao Chen
- The Center of Pathological Diagnosis and Research, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Zeyan Li
- Renmin Hospital of Wuhan University, Wuhan, Hubei, China
| | - Meihua Liang
- The Center of Pathological Diagnosis and Research, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Ziyang Zhang
- Guangzhou Huayin Medical Laboratory Center, Ltd., Guangzhou, China
| | - Di Zhu
- Department of Clinical Pathology, First Affiliated Hospital of Jinan University, Guangzhou, China
| | - Biyun Lin
- The Center of Pathological Diagnosis and Research, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China
| | - Renyu Zhou
- School of Medicine, Jinan University, Guangzhou, China
| | - Yuanzhi Lu
- The Center of Pathological Diagnosis and Research, Affiliated Hospital of Guangdong Medical University, Zhanjiang, China.
- Department of Clinical Pathology, First Affiliated Hospital of Jinan University, Guangzhou, China.
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Barney DE, Gordon BS, Hennigar SR. REDD1 deletion and treadmill running increase liver hepcidin and gluconeogenic enzymes in male mice. J Nutr Sci 2023; 12:e49. [PMID: 37123395 PMCID: PMC10131055 DOI: 10.1017/jns.2023.37] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 03/17/2023] [Indexed: 05/02/2023] Open
Abstract
The iron-regulatory hormone hepcidin is transcriptionally up-regulated by gluconeogenic signals. Recent evidence suggeststhat increases in circulating hepcidin may decrease dietary iron absorption following prolonged exercise, however evidence is limited on whether gluconeogenic signals contribute to post-exercise increases in hepcidin. Mice with genetic knockout of regulated in development and DNA response-1 (REDD1) display greater glycogen depletion following exercise, possibly indicating greater gluconeogenesis. The objective of the present study was to determine liver hepcidin, markers of gluconeogenesis and iron metabolism in REDD1 knockout and wild-type mice following prolonged exercise. Twelve-week-old male REDD1 knockout and wild-type mice were randomised to rest or 60 min treadmill running with 1, 3 or 6 h recovery (n = 5-8/genotype/group). Liver gene expression of hepcidin (Hamp) and gluconeogenic enzymes (Ppargc1a, Creb3l3, Pck1, Pygl) were determined by qRT-PCR. Effects of genotype, exercise and their interaction were assessed by two-way ANOVAs with Tukey's post-hoc tests, and Pearson correlations were used to assess the relationships between Hamp and study outcomes. Liver Hamp increased 1- and 4-fold at 3 and 6 h post-exercise, compared to rest (P-adjusted < 0⋅009 for all), and was 50% greater in REDD1 knockout compared to wild-type mice (P = 0⋅0015). Liver Ppargc1a, Creb3l3 and Pck1 increased with treadmill running (P < 0⋅0001 for all), and liver Ppargc1a, Pck1 and Pygl were greater with REDD1 deletion (P < 0⋅02 for all). Liver Hamp was positively correlated with liver Creb3l3 (R = 0⋅62, P < 0⋅0001) and Pck1 (R = 0⋅44, P = 0⋅0014). In conclusion, REDD1 deletion and prolonged treadmill running increased liver Hamp and gluconeogenic regulators of Hamp, suggesting gluconeogenic signalling of hepcidin with prolonged exercise.
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Affiliation(s)
- David E. Barney
- Department of Nutrition & Integrative Physiology, Florida State University, Tallahassee, FL, USA
- Pennington Biomedical Research Center, Baton Rouge, LA, USA
| | - Bradley S. Gordon
- Department of Nutrition & Integrative Physiology, Florida State University, Tallahassee, FL, USA
| | - Stephen R. Hennigar
- Pennington Biomedical Research Center, Baton Rouge, LA, USA
- Corresponding author: Stephen R. Hennigar, email
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5
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Hain BA, Waning DL. Bone-Muscle Crosstalk: Musculoskeletal Complications of Chemotherapy. Curr Osteoporos Rep 2022; 20:433-441. [PMID: 36087213 DOI: 10.1007/s11914-022-00749-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/26/2022] [Indexed: 01/30/2023]
Abstract
PURPOSE OF REVIEW Chemotherapy drugs combat tumor cells and reduce metastasis. However, a significant side effect of some chemotherapy strategies is loss of skeletal muscle and bone. In cancer patients, maintenance of lean tissue is a positive prognostic indicator of outcomes and helps to minimize the toxicity associated with chemotherapy. Bone-muscle crosstalk plays an important role in the function of the musculoskeletal system and this review will focus on recent findings in preclinical and clinical studies that shed light on chemotherapy-induced bone-muscle crosstalk. RECENT FINDINGS Chemotherapy-induced loss of bone and skeletal muscle are important clinical problems. Bone antiresorptive drugs prevent skeletal muscle weakness in preclinical models. Chemotherapy-induced loss of bone can cause muscle weakness through both changes in endocrine signaling and mechanical loading between muscle and bone. Chemotherapy-induced changes to bone-muscle crosstalk have implications for treatment strategies and patient quality of life. Recent findings have begun to determine the role of chemotherapy in bone-muscle crosstalk and this review summarizes the most relevant clinical and preclinical studies.
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Affiliation(s)
- Brian A Hain
- Department of Cellular and Molecular Physiology, The Penn State University College of Medicine, H166, rm. C4710E, 500 University Drive, Hershey, PA, 17033, USA
| | - David L Waning
- Department of Cellular and Molecular Physiology, The Penn State University College of Medicine, H166, rm. C4710E, 500 University Drive, Hershey, PA, 17033, USA.
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6
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Glucocorticoid receptor activation reduces food intake independent of hyperglycemia in zebrafish. Sci Rep 2022; 12:15677. [PMID: 36127383 PMCID: PMC9489701 DOI: 10.1038/s41598-022-19572-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 08/31/2022] [Indexed: 11/08/2022] Open
Abstract
Chronic cortisol exposure suppresses food intake in fish, but the central mechanism(s) involved in appetite regulation are unclear. Stress and the associated increase in cortisol levels increase hepatic gluconeogenesis, leading to hyperglycemia. As hyperglycemia causes a reduction in food intake, we tested the hypothesis that cortisol-induced hyperglycemia suppresses feeding in zebrafish (Danio rerio). We first established that stress-independent hyperglycemia suppressed food intake, and this corresponded with a reduction in the phosphorylation of the nutrient sensor, AMP-activated protein kinase (AMPK) in the brain. Chronic cortisol exposure also led to hyperglycemia and reduced food intake, but the mechanisms were distinct. In cortisol-exposed fish, there were no changes in brain glucose uptake or AMPK phosphorylation. Also, the phosphorylation of Akt and mTOR was reduced along with an increase in redd1, suggesting an enhanced capacity for proteolysis. Loss of the glucocorticoid receptor did not rescue cortisol-mediated feeding suppression but did increase glucose uptake and abolished the changes seen in mTOR phosphorylation and redd1 transcript abundance. Taken together, our results indicate that GR activation enhances brain proteolysis, and the associated amino acids levels, and not hyperglycemia, maybe a key mediator of the feeding suppression in response to chronic cortisol stimulation in zebrafish.
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7
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Dunlap KR, Laskin GR, Waddell DS, Black AJ, Steiner JL, Vied C, Gordon BS. Aerobic exercise-mediated changes in the expression of glucocorticoid responsive genes in skeletal muscle differ across the day. Mol Cell Endocrinol 2022; 550:111652. [PMID: 35461977 DOI: 10.1016/j.mce.2022.111652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 03/30/2022] [Accepted: 04/18/2022] [Indexed: 10/18/2022]
Abstract
Glucocorticoids are released in response to acute aerobic exercise. The objective was to define changes in the expression of glucocorticoid target genes in skeletal muscle in response to acute aerobic exercise at different times of day. We identified glucocorticoid target genes altered in skeletal muscle by acute exercise by comparing data sets from rodents subjected to acute aerobic exercise in the light or dark cycles to data sets from C2C12 myotubes treated with glucocorticoids. The role of glucocorticoid receptor signaling and REDD1 protein in mediating gene expression was assessed in exercised mice. Changes to expression of glucocorticoid genes were greater when exercise occurred in the dark cycle. REDD1 was required for the induction of genes induced at both times of day. In all, the time of day at which aerobic exercise is conducted dictates changes to the expression of glucocorticoid target genes in skeletal muscle with REDD1 contributing to those changes.
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Affiliation(s)
- Kirsten R Dunlap
- Department of Nutrition and Integrative Physiology, Florida State University, 600 W. Cottage Avenue, Tallahassee, FL, 32306, USA
| | - Grant R Laskin
- Department of Nutrition and Integrative Physiology, Florida State University, 600 W. Cottage Avenue, Tallahassee, FL, 32306, USA
| | - David S Waddell
- Department of Biology, University of North Florida, 1 UNF Drive, Jacksonville, FL, 32224, USA
| | - Adam J Black
- Department of Cell Biology and Physiology, University of North Carolina, 111 Mason Farm Rd, Chapel Hill, NC, 27599, USA
| | - Jennifer L Steiner
- Department of Nutrition and Integrative Physiology, Florida State University, 600 W. Cottage Avenue, Tallahassee, FL, 32306, USA; Institute of Sports Sciences and Medicine, Florida State University, 600 W. Cottage Ave, Tallahassee, FL, 32306, USA
| | - Cynthia Vied
- Translational Sciences Laboratory, Florida State University College of Medicine, 1115 West Call Street, Tallahassee, FL, 32306, USA
| | - Bradley S Gordon
- Department of Nutrition and Integrative Physiology, Florida State University, 600 W. Cottage Avenue, Tallahassee, FL, 32306, USA; Institute of Sports Sciences and Medicine, Florida State University, 600 W. Cottage Ave, Tallahassee, FL, 32306, USA.
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8
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Stott Bond NL, Dréau D, Marriott I, Bennett JM, Turner MJ, Arthur ST, Marino JS. Low-Dose Metformin as a Monotherapy Does Not Reduce Non-Small-Cell Lung Cancer Tumor Burden in Mice. Biomedicines 2021; 9:biomedicines9111685. [PMID: 34829914 PMCID: PMC8615566 DOI: 10.3390/biomedicines9111685] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 11/10/2021] [Accepted: 11/11/2021] [Indexed: 11/16/2022] Open
Abstract
Non-small-cell lung cancer (NSCLC) makes up 80-85% of lung cancer diagnoses. Lung cancer patients undergo surgical procedures, chemotherapy, and/or radiation. Chemotherapy and radiation can induce deleterious systemic side effects, particularly within skeletal muscle. To determine whether metformin reduces NSCLC tumor burden while maintaining skeletal muscle health, C57BL/6J mice were injected with Lewis lung cancer (LL/2), containing a bioluminescent reporter for in vivo tracking, into the left lung. Control and metformin (250 mg/kg) groups received treatments twice weekly. Skeletal muscle was analyzed for changes in genes and proteins related to inflammation, muscle mass, and metabolism. The LL/2 model effectively mimics lung cancer growth and tumor burden. The in vivo data indicate that metformin as administered was not associated with significant improvement in tumor burden in this immunocompetent NSCLC model. Additionally, metformin was not associated with significant changes in key tumor cell division and inflammation markers, or improved skeletal muscle health. Metformin treatment, while exhibiting anti-neoplastic characteristics in many cancers, appears not to be an appropriate monotherapy for NSCLC tumor growth in vivo. Future studies should pursue co-treatment modalities, with metformin as a potentially supportive drug rather than a monotherapy to mitigate cancer progression.
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Affiliation(s)
- Nicole L. Stott Bond
- Distance Education, Technology and Integration, University of North Georgia, Dahlonega, GA 30597, USA;
- Laboratory of Systems Physiology, Department of Applied Physiology, Health, and Clinical Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA; (M.J.T.); (S.T.A.)
| | - Didier Dréau
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA; (D.D.); (I.M.)
| | - Ian Marriott
- Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA; (D.D.); (I.M.)
| | - Jeanette M. Bennett
- Department of Psychological Science, University of North Carolina at Charlotte, Charlotte, NC 28223, USA;
| | - Michael J. Turner
- Laboratory of Systems Physiology, Department of Applied Physiology, Health, and Clinical Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA; (M.J.T.); (S.T.A.)
| | - Susan T. Arthur
- Laboratory of Systems Physiology, Department of Applied Physiology, Health, and Clinical Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA; (M.J.T.); (S.T.A.)
| | - Joseph S. Marino
- Laboratory of Systems Physiology, Department of Applied Physiology, Health, and Clinical Sciences, University of North Carolina at Charlotte, Charlotte, NC 28223, USA; (M.J.T.); (S.T.A.)
- Correspondence:
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9
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Hain BA, Xu H, VanCleave AM, Gordon BS, Kimball SR, Waning DL. REDD1 deletion attenuates cancer cachexia in mice. J Appl Physiol (1985) 2021; 131:1718-1730. [PMID: 34672766 PMCID: PMC10392697 DOI: 10.1152/japplphysiol.00536.2021] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cancer cachexia is a wasting disorder associated with advanced cancer that contributes to mortality. Cachexia is characterized by involuntary loss of body weight and muscle weakness that affects physical function. Regulated in DNA damage and development 1 (REDD1) is a stress-response protein that is transcriptionally upregulated in muscle during wasting conditions and inhibits mechanistic target of rapamycin complex 1 (mTORC1). C2C12 myotubes treated with Lewis lung carcinoma (LLC)-conditioned media increased REDD1 mRNA expression and decreased myotube diameter. To investigate the role of REDD1 in cancer cachexia, we inoculated 12-week old male wild-type or global REDD1 knockout (REDD1 KO) mice with LLC cells and euthanized 28-days later. Wild-type mice had increased skeletal muscle REDD1 expression, and REDD1 deletion prevented loss of body weight and lean tissue mass, but not fat mass. We found that REDD1 deletion attenuated loss of individual muscle weights and loss of myofiber cross sectional area. We measured markers of the Akt/mTORC1 pathway and found that, unlike wild-type mice, phosphorylation of both Akt and 4E-BP1 was maintained in the muscle of REDD1 KO mice after LLC inoculation, suggesting that loss of REDD1 is beneficial in maintaining mTORC1 activity in mice with cancer cachexia. We measured Foxo3a phosphorylation as a marker of the ubiquitin proteasome pathway and autophagy and found that REDD1 deletion prevented dephosphorylation of Foxo3a in muscles from cachectic mice. Our data provides evidence that REDD1 plays an important role in cancer cachexia through the regulation of both protein synthesis and protein degradation pathways.
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Affiliation(s)
- Brian A Hain
- The Penn State College of Medicine, Dept. of Cellular and Molecular Physiology, Hershey, PA, United States.,Penn State Cancer Institute, Hershey, PA, United States
| | - Haifang Xu
- The Penn State College of Medicine, Dept. of Cellular and Molecular Physiology, Hershey, PA, United States
| | - Ashley M VanCleave
- The Penn State College of Medicine, Dept. of Cellular and Molecular Physiology, Hershey, PA, United States
| | - Bradley S Gordon
- Florida State University, Dept. of Nutrition and Integrative Physiology, Tallahassee, FL, United States
| | - Scot R Kimball
- The Penn State College of Medicine, Dept. of Cellular and Molecular Physiology, Hershey, PA, United States
| | - David L Waning
- The Penn State College of Medicine, Dept. of Cellular and Molecular Physiology, Hershey, PA, United States.,Penn State Cancer Institute, Hershey, PA, United States
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10
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van Zyl E, Tolls V, Blackmore A, McKay BC. Isoginkgetin leads to decreased protein synthesis and activates an ATF4-dependent transcriptional response. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2021; 1868:119123. [PMID: 34419492 DOI: 10.1016/j.bbamcr.2021.119123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 08/10/2021] [Accepted: 08/17/2021] [Indexed: 02/05/2023]
Abstract
Isoginkgetin (IGG) is a small molecule inhibitor of pre-mRNA splicing. Failure to accurately remove introns could lead to the production of aberrant mRNAs and proteins. The cellular responses to splicing stress are not well defined. Here, we used oligonucleotide microarrays to assess genome wide changes in gene expression associated with exposure to IGG. Two of the 3 enriched pathways identified using PANTHER analysis of differentially expressed transcripts are linked to the ATF4 transcription factor. We confirmed that ATF4 was selectively translated and upregulated in response IGG despite an almost complete block to total protein synthesis. Importantly, partial disruption of the ATF4 gene using CRISPR-mediated gene editing prevented IGG-induced changes in gene expression. Remarkably, another spliceosome inhibitor, pladienolide B, did not inhibit translation, activate ATF4 or increase ATF4-dependent gene expression. Taken together, IGG activates ATF4 and an ATF4-dependent transcriptional response but these effects are not common to all spliceosome inhibitors.
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Affiliation(s)
- Erin van Zyl
- Department of Biology, Carleton University, Ottawa, ON, Canada
| | - Victoria Tolls
- Department of Biology, Carleton University, Ottawa, ON, Canada
| | - Alex Blackmore
- Department of Biology, Carleton University, Ottawa, ON, Canada
| | - Bruce C McKay
- Department of Biology, Carleton University, Ottawa, ON, Canada; Department of Biology, Carleton University, Ottawa, ON, Canada.
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11
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Fattahi F, Kiani J, Alemrajabi M, Soroush A, Naseri M, Najafi M, Madjd Z. Overexpression of DDIT4 and TPTEP1 are associated with metastasis and advanced stages in colorectal cancer patients: a study utilizing bioinformatics prediction and experimental validation. Cancer Cell Int 2021; 21:303. [PMID: 34107956 PMCID: PMC8191213 DOI: 10.1186/s12935-021-02002-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 06/01/2021] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Various diagnostic and prognostic tools exist in colorectal cancer (CRC) due to multiple genetic and epigenetic alterations causing the disease. Today, the expression of RNAs is being used as prognostic markers for cancer. METHODS In the current study, various dysregulated RNAs in CRC were identified via bioinformatics prediction. Expression of several of these RNAs were measured by RT-qPCR in 48 tissues from CRC patients as well as in colorectal cancer stem cell-enriched spheroids derived from the HT-29 cell line. The relationships between the expression levels of these RNAs and clinicopathological features were analyzed. RESULTS Our bioinformatics analysis determined 11 key mRNAs, 9 hub miRNAs, and 18 lncRNAs which among them 2 coding RNA genes including DDIT4 and SULF1 as well as 3 non-coding RNA genes including TPTEP1, miR-181d-5p, and miR-148b-3p were selected for the further investigations. Expression of DDIT4, TPTEP1, and miR-181d-5p showed significantly increased levels while SULF1 and miR-148b-3p showed decreased levels in CRC tissues compared to the adjacent normal tissues. Positive relationships between DDIT4, SULF1, and TPTEP1 expression and metastasis and advanced stages of CRC were observed. Additionally, our results showed significant correlations between expression of TPTEP1 with DDIT4 and SULF1. CONCLUSIONS Our findings demonstrated increased expression levels of DDIT4 and TPTEP1 in CRC were associated with more aggressive tumor behavior and more advanced stages of the disease. The positive correlations between TPTEP1 as non-coding RNA and both DDIT4 and SULF1 suggest a regulatory effect of TPTEP1 on these genes.
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Affiliation(s)
- Fahimeh Fattahi
- Oncopathology Research Center, Iran University of Medical Sciences, (IUMS), Tehran, Iran.,Department of Molecular Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Jafar Kiani
- Oncopathology Research Center, Iran University of Medical Sciences, (IUMS), Tehran, Iran.,Department of Molecular Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mahdi Alemrajabi
- Firoozgar Clinical Research Development Center (FCRDC), Iran University of Medical Sciences, Tehran, Iran
| | - Ahmadreza Soroush
- Obesity and Eating Habits Research Center, Endocrinology and Metabolism Clinical Sciences Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Marzieh Naseri
- Oncopathology Research Center, Iran University of Medical Sciences, (IUMS), Tehran, Iran.,Department of Molecular Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Mohammad Najafi
- Biochemistry Department, Faculty of Medical Sciences, Iran University of Medical Sciences, Tehran, Iran.
| | - Zahra Madjd
- Oncopathology Research Center, Iran University of Medical Sciences, (IUMS), Tehran, Iran. .,Department of Molecular Medicine, Faculty of Advanced Technologies in Medicine, Iran University of Medical Sciences, Tehran, Iran.
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12
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Rosa-Caldwell ME, Lim S, Haynie WA, Brown JL, Deaver JW, Morena Da Silva F, Jansen LT, Lee DE, Wiggs MP, Washington TA, Greene NP. Female mice may have exacerbated catabolic signalling response compared to male mice during development and progression of disuse atrophy. J Cachexia Sarcopenia Muscle 2021; 12:717-730. [PMID: 33675163 PMCID: PMC8200438 DOI: 10.1002/jcsm.12693] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/11/2020] [Revised: 01/28/2021] [Accepted: 02/01/2021] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Muscle atrophy is a common pathology associated with disuse, such as prolonged bed rest or spaceflight, and is associated with detrimental health outcomes. There is emerging evidence that disuse atrophy may differentially affect males and females. Cellular mechanisms contributing to the development and progression of disuse remain elusive, particularly protein turnover cascades. The purpose of this study was to investigate the initial development and progression of disuse muscle atrophy in male and female mice using the well-established model of hindlimb unloading (HU). METHODS One hundred C57BL/6J mice (50 male and 50 female) were hindlimb suspended for 0 (control), 24, 48, 72, or 168 h to induce disuse atrophy (10 animals per group). At designated time points, animals were euthanized, and tissues (extensor digitorum longus, gastrocnemius, and soleus for mRNA analysis, gastrocnemius and extensor digitorum longus for protein synthesis rates, and tibialis anterior for histology) were collected for analysis of protein turnover mechanisms (protein anabolism and catabolism). RESULTS Both males and females lost ~30% of tibialis anterior cross-sectional area after 168 h of disuse. Males had no statistical difference in MHCIIB fibre area, whereas unloaded females had ~33% lower MHCIIB cross-sectional area by 168 h of unloading. Both males and females had lower fractional protein synthesis rates (FSRs) within 24-48 h of HU, and females appeared to have a greater reduction compared with males within 24 h of HU (~23% lower FSRs in males vs. 40% lower FSRs in females). Males and females exhibited differential patterns and responses in multiple markers of protein anabolism, catabolism, and myogenic capacity during the development and progression of disuse atrophy. Specifically, females had greater mRNA inductions of catabolic factors Ubc and Gadd45a (~4-fold greater content in females compared with ~2-fold greater content in males) and greater inductions of anabolic inhibitors Redd1 and Deptor with disuse across multiple muscle tissues exhibiting different fibre phenotypes. CONCLUSIONS These results suggest that the aetiology of disuse muscle atrophy is more complicated and nuanced than previously thought, with different responses based on muscle phenotypes and between males and females, with females having greater inductions of atrophic markers early in the development of disuse atrophy.
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Affiliation(s)
- Megan E Rosa-Caldwell
- Cachexia Research Laboratory, Exercise Science Research Center, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA
| | - Seongkyun Lim
- Cachexia Research Laboratory, Exercise Science Research Center, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA
| | - Wesley A Haynie
- Exercise Muscle Biology Laboratory, Exercise Science Research Center, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA
| | - Jacob L Brown
- Cachexia Research Laboratory, Exercise Science Research Center, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA
| | - John William Deaver
- Cachexia Research Laboratory, Exercise Science Research Center, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA
| | - Francielly Morena Da Silva
- Cachexia Research Laboratory, Exercise Science Research Center, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA
| | - Lisa T Jansen
- Cachexia Research Laboratory, Exercise Science Research Center, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA
| | - David E Lee
- Cachexia Research Laboratory, Exercise Science Research Center, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA
| | - Michael P Wiggs
- Integrative Physiology and Nutrition Laboratory Name, Department of Health and Kinesiology, University of Texas at Tyler, Tyler, TX, USA.,Department of Health, Human Performance and Recreation, Baylor University, Waco, TX, USA
| | - Tyrone A Washington
- Exercise Muscle Biology Laboratory, Exercise Science Research Center, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA
| | - Nicholas P Greene
- Cachexia Research Laboratory, Exercise Science Research Center, Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, AR, USA
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13
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Diurnal variation in gene expression of human peripheral blood mononuclear cells after eating a standard meal compared with a high protein meal: A cross-over study. Clin Nutr 2021; 40:4349-4359. [DOI: 10.1016/j.clnu.2021.01.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Revised: 01/03/2021] [Accepted: 01/07/2021] [Indexed: 01/27/2023]
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14
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Savukaitytė A, Gudoitytė G, Bartnykaitė A, Ugenskienė R, Juozaitytė E. siRNA Knockdown of REDD1 Facilitates Aspirin-Mediated Dephosphorylation of mTORC1 Target 4E-BP1 in MDA-MB-468 Human Breast Cancer Cell Line. Cancer Manag Res 2021; 13:1123-1133. [PMID: 33574709 PMCID: PMC7872862 DOI: 10.2147/cmar.s264414] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2020] [Accepted: 12/11/2020] [Indexed: 12/17/2022] Open
Abstract
Background Mutations within genes encoding components of the PI3K/AKT/mTOR (phosphoinositide 3-kinase/protein kinase B/mechanistic target of rapamycin) signaling axis frequently activate the pathway in breast cancer, making it an attractive therapeutic target. Inhibition of mTORC1 (mechanistic target of rapamycin complex 1) activity upon aspirin treatment has been reported in breast cancer cells harboring PI3KCA (phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit alpha) mutation and is considered to account for anticancer action. Methods MDA-MB-468 (harbors mutated PTEN (phosphatase and TENsin homolog)), MCF-7 (PI3KCA-mutated), MDA-MB-231 (no PI3K pathway mutations) cancer cell lines and MCF10A non-cancerous breast epithelial cells were employed for the assessment of modulation of mTORC1 signaling by aspirin. Targeted amplicon-based next-generation sequencing using the Ion Torrent technology was carried out to determine gene expression changes following drug treatment. Western blot was performed to analyze the expression and phosphorylation of proteins. Knockdown by siRNA approach was applied to assess the role of REDD1/DDIT4 (DNA damage-inducible transcript 4) in mTORC1 inhibition by aspirin. Results We show a decline in phosphorylation of mTORC1 downstream substrate 4E-BP1 (eukaryotic translation initiation factor 4E-binding protein 1) in response to treatment with aspirin and its metabolite salicylic acid in MDA-MB-468, MCF-7, MDA-MB-231, and MCF10A cell lines. We further demonstrate a novel molecular response to aspirin in breast cancer cells. Specifically, we found that aspirin and salicylic acid increase the expression of REDD1 protein, that is known for its suppressive function towards mTORC1. Unexpectedly, we observed that siRNA knockdown of REDD1 expression facilitated aspirin-mediated suppression of mTORC1 downstream substrate 4E-BP1 phosphorylation in the MDA-MB-468 cell line. REDD1 downregulation slightly encouraged reduction in 4E-BP1 phosphorylation by aspirin in MCF-7 cells but did not elicit a reproducible effect in the MDA-MB-231 cell line. siRNA knockdown of REDD1 did not affect the expression of phosphorylated form of 4E-BP1 following aspirin treatment in MCF10A non-cancerous breast epithelial cells. Conclusion The current findings suggest that REDD1 downregulation might improve the anticancer activity of aspirin in a subset of breast tumors.
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Affiliation(s)
- Aistė Savukaitytė
- Oncology Research Laboratory, Institute of Oncology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Greta Gudoitytė
- Oncology Research Laboratory, Institute of Oncology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Agnė Bartnykaitė
- Oncology Research Laboratory, Institute of Oncology, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Rasa Ugenskienė
- Oncology Research Laboratory, Institute of Oncology, Lithuanian University of Health Sciences, Kaunas, Lithuania.,Institute of Biology Systems and Genetic Research, Lithuanian University of Health Sciences, Kaunas, Lithuania
| | - Elona Juozaitytė
- Department of Oncology and Hematology, Hospital of Lithuanian University of Health Sciences Kaunas Clinics, Kaunas, Lithuania
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15
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Mirzoev TM. Skeletal Muscle Recovery from Disuse Atrophy: Protein Turnover Signaling and Strategies for Accelerating Muscle Regrowth. Int J Mol Sci 2020; 21:ijms21217940. [PMID: 33114683 PMCID: PMC7663166 DOI: 10.3390/ijms21217940] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Revised: 10/08/2020] [Accepted: 10/23/2020] [Indexed: 12/15/2022] Open
Abstract
Skeletal muscle fibers have a unique capacity to adjust their metabolism and phenotype in response to alternations in mechanical loading. Indeed, chronic mechanical loading leads to an increase in skeletal muscle mass, while prolonged mechanical unloading results in a significant decrease in muscle mass (muscle atrophy). The maintenance of skeletal muscle mass is dependent on the balance between rates of muscle protein synthesis and breakdown. While molecular mechanisms regulating protein synthesis during mechanical unloading have been relatively well studied, signaling events implicated in protein turnover during skeletal muscle recovery from unloading are poorly defined. A better understanding of the molecular events that underpin muscle mass recovery following disuse-induced atrophy is of significant importance for both clinical and space medicine. This review focuses on the molecular mechanisms that may be involved in the activation of protein synthesis and subsequent restoration of muscle mass after a period of mechanical unloading. In addition, the efficiency of strategies proposed to improve muscle protein gain during recovery is also discussed.
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Affiliation(s)
- Timur M Mirzoev
- Myology Laboratory, Institute of Biomedical Problems RAS, Moscow 123007, Russia
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16
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Tyagi SC, Stanisic D, Singh M. Epigenetic memory: gene writer, eraser and homocysteine. Mol Cell Biochem 2020; 476:507-512. [PMID: 33030620 DOI: 10.1007/s11010-020-03895-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Accepted: 08/31/2020] [Indexed: 10/23/2022]
Abstract
Naturally chromatin remodeling is highly organized, consisting of histone acetylation (opening/relaxation of the compact chromatin structure), DNA methylation (inhibition of the gene expression activity) and sequence rearrangement by shifting. All this is essentially required for proper "in-printing and off-printing" of genes thus ensuring the epigenetic memory process. Any imbalance in ratios of DNA methyltransferase (DNMT, gene writer), fat-mass obesity-associated protein (FTO, gene eraser) and product (function) homocysteine (Hcy) could lead to numerous diseases. Interestingly, a similar process also happens in stem cells during embryogenesis and development. Despite gigantic unsuccessful efforts undertaken thus far toward the conversion of a stem cell into a functional cardiomyocyte, there has been hardly any study that shows successful conversion of a stem cell into a multinucleated cardiomyocyte. We have shown nuclear hypertrophy during heart failure, however; the mechanism(s) of epigenetic memory, regulation of genes during fertilization, embryogenesis, development and during adulthood remain far from understanding. In addition, there may be a connection of aging, loosing of the memory leading to death, and presumably to reincarnation. This review highlights some of these pertinent issues facing the discipline of biology as a whole today.
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Affiliation(s)
- Suresh C Tyagi
- Department of Physiology, University of Louisville School of Medicine, Louisville, KY, 40202, USA
| | - Dragana Stanisic
- Department of Physiology, University of Louisville School of Medicine, Louisville, KY, 40202, USA.,Department of Dentistry, Faculty of Medical Sciences, University of Kragujevac, 34000, Kragujevac, Serbia
| | - Mahavir Singh
- Department of Physiology, University of Louisville School of Medicine, Louisville, KY, 40202, USA.
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17
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Rev-erbα heterozygosity produces a dose-dependent phenotypic advantage in mice. PLoS One 2020; 15:e0227720. [PMID: 32407314 PMCID: PMC7224546 DOI: 10.1371/journal.pone.0227720] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 04/27/2020] [Indexed: 01/01/2023] Open
Abstract
Numerous mutational studies have demonstrated that circadian clock proteins regulate behavior and metabolism. Nr1d1(Rev-erbα) is a key regulator of circadian gene expression and a pleiotropic regulator of skeletal muscle homeostasis and lipid metabolism. Loss of Rev-erbα expression induces muscular atrophy, high adiposity, and metabolic syndrome in mice. Here we show that, unlike knockout mice, Nr1d1 heterozygous mice are not susceptible to muscular atrophy and in fact paradoxically possess larger myofiber diameters and improved neuromuscular function, compared to wildtype mice. Heterozygous mice lacked dyslipidemia, a characteristic of Nr1d1 knockout mice and displayed increased whole-body fatty-acid oxidation during periods of inactivity (light cycle). Heterozygous mice also exhibited higher rates of glucose uptake when fasted, and had elevated basal rates of gluconeogenesis compared to wildtype and knockout littermates. Rev-erbα ablation suppressed glycolysis and fatty acid-oxidation in white-adipose tissue (WAT), whereas partial Rev-erbα loss, curiously stimulated these processes. Our investigations revealed that Rev-erbα dose-dependently regulates glucose metabolism and fatty acid oxidation in WAT and muscle.
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18
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Qiao S, Koh SB, Vivekanandan V, Salunke D, Patra KC, Zaganjor E, Ross K, Mizukami Y, Jeanfavre S, Chen A, Mino-Kenudson M, Ramaswamy S, Clish C, Haigis M, Bardeesy N, Ellisen LW. REDD1 loss reprograms lipid metabolism to drive progression of RAS mutant tumors. Genes Dev 2020; 34:751-766. [PMID: 32273287 PMCID: PMC7263146 DOI: 10.1101/gad.335166.119] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 03/19/2020] [Indexed: 12/15/2022]
Abstract
In this study, Qiao et al. set out to investigate the role of REDD1 in the development of KRAS-driven tumors. Using genetically engineered mouse models, the authors show that loss of REDD1 promotes the development of oncogenic KRAS-driven pancreatic and lung cancers. Additionally, the authors use a combination of transcriptomic and metabolomic analyses to show that REDD1 deficiency induces lipid uptake, enhances fatty acid oxidation, and suppresses de novo lipid biosynthesis, in particular under hypoxia conditions, which plays an important role for the redox homeostasis of tumor cells through the regulation of NADPH levels. Human cancers with activating RAS mutations are typically highly aggressive and treatment-refractory, yet RAS mutation itself is insufficient for tumorigenesis, due in part to profound metabolic stress induced by RAS activation. Here we show that loss of REDD1, a stress-induced metabolic regulator, is sufficient to reprogram lipid metabolism and drive progression of RAS mutant cancers. Redd1 deletion in genetically engineered mouse models (GEMMs) of KRAS-dependent pancreatic and lung adenocarcinomas converts preneoplastic lesions into invasive and metastatic carcinomas. Metabolic profiling reveals that REDD1-deficient/RAS mutant cells exhibit enhanced uptake of lysophospholipids and lipid storage, coupled to augmented fatty acid oxidation that sustains both ATP levels and ROS-detoxifying NADPH. Mechanistically, REDD1 loss triggers HIF-dependent activation of a lipid storage pathway involving PPARγ and the prometastatic factor CD36. Correspondingly, decreased REDD1 expression and a signature of REDD1 loss predict poor outcomes selectively in RAS mutant but not RAS wild-type human lung and pancreas carcinomas. Collectively, our findings reveal the REDD1-mediated stress response as a novel tumor suppressor whose loss defines a RAS mutant tumor subset characterized by reprogramming of lipid metabolism, invasive and metastatic progression, and poor prognosis. This work thus provides new mechanistic and clinically relevant insights into the phenotypic heterogeneity and metabolic rewiring that underlies these common cancers.
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Affiliation(s)
- Shuxi Qiao
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA.,Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Siang-Boon Koh
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA.,Harvard Medical School, Boston, Massachusetts 02115, USA
| | | | - Devika Salunke
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA
| | - Krushna Chandra Patra
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA.,Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Elma Zaganjor
- Ludwig Cancer Center at Harvard, Harvard University, Boston, Massachusetts 02115, USA
| | - Kenneth Ross
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA.,Harvard Medical School, Boston, Massachusetts 02115, USA.,Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, Massachusetts 02142, USA
| | - Yusuke Mizukami
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA.,Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Sarah Jeanfavre
- Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, Massachusetts 02142, USA
| | - Athena Chen
- Harvard Medical School, Boston, Massachusetts 02115, USA.,Department of Pathology, Massachusetts General Hospital, Massachusetts 02114, USA
| | - Mari Mino-Kenudson
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA.,Harvard Medical School, Boston, Massachusetts 02115, USA.,Department of Pathology, Massachusetts General Hospital, Massachusetts 02114, USA
| | - Sridhar Ramaswamy
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA.,Harvard Medical School, Boston, Massachusetts 02115, USA.,Ludwig Cancer Center at Harvard, Harvard University, Boston, Massachusetts 02115, USA.,Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, Massachusetts 02142, USA
| | - Clary Clish
- Broad Institute of Massachusetts Institute of Technology and Harvard University, Cambridge, Massachusetts 02142, USA
| | - Marcia Haigis
- Ludwig Cancer Center at Harvard, Harvard University, Boston, Massachusetts 02115, USA
| | - Nabeel Bardeesy
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA.,Harvard Medical School, Boston, Massachusetts 02115, USA
| | - Leif W Ellisen
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts 02114, USA.,Harvard Medical School, Boston, Massachusetts 02115, USA
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19
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Dumas K, Ayachi C, Gilleron J, Lacas‐Gervais S, Pastor F, Favier FB, Peraldi P, Vaillant N, Yvan‐Charvet L, Bonnafous S, Patouraux S, Anty R, Tran A, Gual P, Cormont M, Tanti J, Giorgetti‐Peraldi S. REDD1 deficiency protects against nonalcoholic hepatic steatosis induced by high‐fat diet. FASEB J 2020; 34:5046-5060. [DOI: 10.1096/fj.201901799rr] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Revised: 01/24/2020] [Accepted: 01/24/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Karine Dumas
- Université Côte d’Azur, Inserm, C3M, Team “Cellular and Molecular Physiopathology of Obesity” France
| | - Chaima Ayachi
- Université Côte d’Azur, Inserm, C3M, Team “Cellular and Molecular Physiopathology of Obesity” France
| | - Jerome Gilleron
- Université Côte d’Azur, Inserm, C3M, Team “Cellular and Molecular Physiopathology of Obesity” France
| | | | - Faustine Pastor
- Université Côte d’Azur, Inserm, C3M, Team “Cellular and Molecular Physiopathology of Obesity” France
| | | | - Pascal Peraldi
- Université Côte d’Azur, Inserm, CNRS, iBV, Team “Stem Cells and Differentiation” France
| | - Nathalie Vaillant
- Université Côte d’Azur, Inserm, C3M, Team “Haematometabolism in Diseases” France
| | - Laurent Yvan‐Charvet
- Université Côte d’Azur, Inserm, C3M, Team “Haematometabolism in Diseases” France
| | - Stéphanie Bonnafous
- Université Côte d’Azur, Inserm, C3M, Team “Chronic Liver Diseases Associated with Steatosis and Alcohol” France
- Université Côte d’Azur, CHU, Inserm, C3M,Team “Chronic Liver Diseases Associated with Steatosis and Alcohol” France
| | - Stéphanie Patouraux
- Université Côte d’Azur, Inserm, C3M, Team “Chronic Liver Diseases Associated with Steatosis and Alcohol” France
- Université Côte d’Azur, CHU, Inserm, C3M,Team “Chronic Liver Diseases Associated with Steatosis and Alcohol” France
| | - Rodolphe Anty
- Université Côte d’Azur, Inserm, C3M, Team “Chronic Liver Diseases Associated with Steatosis and Alcohol” France
- Université Côte d’Azur, CHU, Inserm, C3M,Team “Chronic Liver Diseases Associated with Steatosis and Alcohol” France
| | - Albert Tran
- Université Côte d’Azur, Inserm, C3M, Team “Chronic Liver Diseases Associated with Steatosis and Alcohol” France
- Université Côte d’Azur, CHU, Inserm, C3M,Team “Chronic Liver Diseases Associated with Steatosis and Alcohol” France
| | - Philippe Gual
- Université Côte d’Azur, Inserm, C3M, Team “Chronic Liver Diseases Associated with Steatosis and Alcohol” France
| | - Mireille Cormont
- Université Côte d’Azur, Inserm, C3M, Team “Cellular and Molecular Physiopathology of Obesity” France
| | - Jean‐François Tanti
- Université Côte d’Azur, Inserm, C3M, Team “Cellular and Molecular Physiopathology of Obesity” France
| | - Sophie Giorgetti‐Peraldi
- Université Côte d’Azur, Inserm, C3M, Team “Cellular and Molecular Physiopathology of Obesity” France
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20
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Adegoke OAJ, Beatty BE, Kimball SR, Wing SS. Interactions of the super complexes: When mTORC1 meets the proteasome. Int J Biochem Cell Biol 2019; 117:105638. [PMID: 31678320 PMCID: PMC6910232 DOI: 10.1016/j.biocel.2019.105638] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Revised: 10/18/2019] [Accepted: 10/20/2019] [Indexed: 12/30/2022]
Abstract
Homeostatic regulation of energy and metabolic status requires that anabolic and catabolic signaling pathways be precisely regulated and coordinated. Mammalian/mechanistic target of rapamycin complex 1 (mTORC1) is a mega protein complex that promotes energy-consuming anabolic processes of protein and nucleic acid synthesis as well lipogenesis in times of energy and nutrient abundance. However, it is best characterized as the regulator of steps leading to protein synthesis. The ubiquitin-proteasome proteolytic system (UPS) is a major intracellular proteolytic system whose activity is increased during periods of nutrient scarcity and in muscle wasting conditions such as cachexia. Recent studies have examined the impact of mTORC1 on levels and functions of the 26S proteasome, the mega protease complex of the UPS. Here we first briefly review current understanding of the regulation of mTORC1, the UPS, and the 26S proteasome complex. We then review evidence of the effect of each complex on the abundance and functions of the other. Given the fact that drugs that inhibit either complex are either in clinical trials or are approved for treatment of cancer, a muscle wasting condition, we identify studying the effect of combinatory mTORC1-proteasome inhibition on skeletal muscle mass and health as a critical area requiring investigation.
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Affiliation(s)
- Olasunkanmi A J Adegoke
- School of Kinesiology and Health Science, and Muscle Health Research Centre, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3 Canada.
| | - Brendan E Beatty
- School of Kinesiology and Health Science, and Muscle Health Research Centre, York University, 4700 Keele Street, Toronto, Ontario, M3J 1P3 Canada
| | - Scot R Kimball
- Department of Cellular and Molecular Physiology, The Pennsylvania State University College of Medicine, Hershey, PA 17033, USA
| | - Simon S Wing
- Department of Medicine, McGill University and the Research Institute of the McGill University Health Centre, the Montreal Diabetes Research Centre, Montréal, Quebec, H4A 3J1. Canada
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21
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Cholesterol Prevents Hypoxia-Induced Hypoglycemia by Regulation of a Metabolic Ketogenic Shift. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2019; 2019:5829357. [PMID: 31612075 PMCID: PMC6755303 DOI: 10.1155/2019/5829357] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 07/11/2019] [Accepted: 08/19/2019] [Indexed: 12/30/2022]
Abstract
Blood cholesterol levels have been connected to high-altitude adaptation. In the present study, we treated mice with high-cholesterol diets following exposure to acute hypoxic stress and evaluated the effects of the diets on whole-body, liver glucose, and liver fat metabolism. For rapid cholesterol liver uptake, 6-week-old male C57BL/J6 mice were fed with high-cholesterol/cholic acid (CH) diet for 6 weeks and then were exposed to gradual oxygen level reduction for 1 h and hypoxia at 7% oxygen for additional 1 hour using a hypoxic chamber. Animals were than sacrificed, and metabolic markers were evaluated. Hypoxic treatment had a strong hypoglycemic effect that was completely blunted by CH treatment. Decreases in gluconeogenesis and glycogenolysis as well as an increase in ketone body formation were observed. Such changes indicate a metabolic shift from glucose to fat utilization due to activation of the inducible nitric oxide synthase/AMPK axis in the CH-treated animals. Increased ketogenesis was also observed in vitro in hepatocytes after cholesterol treatment. In conclusion, our results show for the first time that cholesterol contributes to metabolic shift and adaptation to hypoxia in vivo and in vitro through induction of HIF-1α and iNOS expression.
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Mohammed A, Cui Y, Mas VR, Kamaleswaran R. Differential gene expression analysis reveals novel genes and pathways in pediatric septic shock patients. Sci Rep 2019; 9:11270. [PMID: 31375728 PMCID: PMC6677896 DOI: 10.1038/s41598-019-47703-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2019] [Accepted: 07/12/2019] [Indexed: 12/20/2022] Open
Abstract
Septic shock is a devastating health condition caused by uncontrolled sepsis. Advancements in high-throughput sequencing techniques have increased the number of potential genetic biomarkers under review. Multiple genetic markers and functional pathways play a part in development and progression of pediatric septic shock. We identified 53 differentially expressed pediatric septic shock biomarkers using gene expression data sampled from 181 patients admitted to the pediatric intensive care unit within the first 24 hours of their admission. The gene expression signatures showed discriminatory power between pediatric septic shock survivors and nonsurvivor types. Using functional enrichment analysis of differentially expressed genes, we validated the known genes and pathways in septic shock and identified the unexplored septic shock-related genes and functional groups. Differential gene expression analysis revealed the genes involved in the immune response, chemokine-mediated signaling, neutrophil chemotaxis, and chemokine activity and distinguished the septic shock survivor from non-survivor. The identification of the septic shock gene biomarkers may facilitate in septic shock diagnosis, treatment, and prognosis.
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Affiliation(s)
- Akram Mohammed
- University of Tennessee Health Science Center, Memphis, TN, USA
| | - Yan Cui
- University of Tennessee Health Science Center, Memphis, TN, USA
| | - Valeria R Mas
- University of Tennessee Health Science Center, Memphis, TN, USA
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Faught E, Vijayan MM. Loss of the glucocorticoid receptor in zebrafish improves muscle glucose availability and increases growth. Am J Physiol Endocrinol Metab 2019; 316:E1093-E1104. [PMID: 30939052 PMCID: PMC6620571 DOI: 10.1152/ajpendo.00045.2019] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Chronic stress and the associated elevation in corticosteroid levels increase muscle protein catabolism. We hypothesized that the glucocorticoid receptor (GR)-regulated restriction of muscle glucose availability may play a role in the increased protein catabolism during chronic stress. To test this, we generated a ubiquitous GR knockout (GRKO) zebrafish to determine the physiological consequence of glucocorticoid stimulation on muscle metabolism and growth. Adult GRKO zebrafish had higher body mass, and this corresponded to an increased protein and lipid, but not carbohydrate, content. GRKO fish were hypercortisolemic, but they elicited a higher cortisol response to an acute stressor. However, the stressor-induced increase in plasma glucose level observed in the wild type was completely abolished in the GRKO fish. Also, the muscle, but not liver, capacity for glucose uptake was enhanced in the GRKO fish, and this corresponded with a higher hexokinase activity in the mutants. Zebrafish lacking GR also showed a higher capacity for protein synthesis, including increased phosphorylation of eukaryotic initiation factor 4B, higher expression of heat shock protein cognate 70, and total protein content. A chronic fasting stressor reduced body mass and muscle protein content in adult zebrafish, but this decrease was attenuated in the GRKO compared with the wild-type fish. Metabolomics analysis revealed that the free pool of amino acid substrates used for oxidation and gluconeogenesis were lower in the fasted GRKO fish muscle compared with the wild type. Altogether, chronic stressor-mediated GR signaling limits muscle glucose uptake, and this may play a role in protein catabolism, leading to the growth suppression in fish.
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Affiliation(s)
- Erin Faught
- Department of Biological Sciences, University of Calgary , Calgary, Alberta , Canada
| | - Mathilakath M Vijayan
- Department of Biological Sciences, University of Calgary , Calgary, Alberta , Canada
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Kruit AS, Smits L, Pouwels A, Schreinemachers MCJM, Hummelink SLM, Ulrich DJO. Ex-vivo perfusion as a successful strategy for reduction of ischemia-reperfusion injury in prolonged muscle flap preservation - A gene expression study. Gene 2019; 701:89-97. [PMID: 30902788 DOI: 10.1016/j.gene.2019.03.021] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 03/10/2019] [Accepted: 03/12/2019] [Indexed: 11/18/2022]
Abstract
INTRODUCTION With the introduction of vascularized composite allotransplantation (VCA) as new surgical technique, the need arose for strategies that could safely prolong graft preservation. Ex-vivo machine perfusion is a promising technique and is currently applied in solid organ transplantation. There is still limited evidence in the field of VCA and free flap transplantation. This gene expression study aimed to assess the degree of ischemia-reperfusion (IR) injury after preservation and replantation of free muscle flaps in a porcine model. MATERIALS AND METHODS A microarray analysis was first conducted on muscle flaps preserved by ex-vivo perfusion versus cold storage, to select genes of interest for further investigation. The expression of these selected genes was then examined in a muscle flap replantation model after 18 hour ex-vivo perfusion (n = 14) using qRT-PCR. Two preservation solutions were compared to static cold storage: University of Wisconsin-mp (n = 5) and Histidine-Tryptophan-Ketoglutarate solution (n = 5). RESULTS A selection of 8 genes was made based on micro-array results: Tumor necrosis factor receptor superfamily member 10-A like, Regulator of G-protein signaling 2, Nuclear factor kappa beta inhibitor zeta, Interleukin-1 beta, Fibroblast growth factor 6 and DNA damage-inducible transcript 4, Hypoxia-inducible factor 1-alpha and Caspase-3. The muscle flap replantation experiment compared their expression patterns before and after preservation and replantation and showed overall comparable gene expression between the preservation groups. CONCLUSIONS The expression of genes related to ischemia, apoptosis and inflammation was comparable between the ex-vivo perfusion and static cold storage groups. These results suggest that ex-vivo perfusion might be a promising technique for 18 hour muscle preservation in terms of decreasing ischemia-reperfusion injury.
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Affiliation(s)
- Anne Sophie Kruit
- Department of Plastic, Reconstructive and Hand Surgery, Radboud University Medical Center, Nijmegen, the Netherlands.
| | - Laura Smits
- Medical Biology, Faculty of Science, Radboud University, Nijmegen, the Netherlands
| | - Angéle Pouwels
- HAN University of Applied Sciences, Nijmegen, the Netherlands
| | | | - Stefan L M Hummelink
- Department of Plastic, Reconstructive and Hand Surgery, Radboud University Medical Center, Nijmegen, the Netherlands
| | - Dietmar J O Ulrich
- Department of Plastic, Reconstructive and Hand Surgery, Radboud University Medical Center, Nijmegen, the Netherlands
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M(en)TORship lessons on life and death by the integrated stress response. Biochim Biophys Acta Gen Subj 2018; 1863:644-649. [PMID: 30572003 DOI: 10.1016/j.bbagen.2018.12.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 12/11/2018] [Accepted: 12/14/2018] [Indexed: 12/20/2022]
Abstract
Cells employ pro-survival and pro-adaptive pathways to cope with different forms of environmental stress. When stress is excessive, and the damage caused by it is unsustainable, cells engage pro-death pathways, which are in place to protect the host from the deleterious effects of harmed cells. Two important pathways that determine the balance between survival and death of stressed cells are the integrated stress response (ISR) and the mammalian target of rapamycin (mTOR), both of which converge at the level of mRNA translation. The two pathways have established avenues of communication to control their activity and determine the fate of stressed cells in a context-dependent manner. The functional interplay between the ISR and mTOR may have significant ramifications in the development and treatment of human diseases such as diabetes, neurodegeneration and cancer.
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Successful Long-term Extracorporeal Perfusion of Free Musculocutaneous Flaps in a Porcine Model. J Surg Res 2018; 235:113-123. [PMID: 30691784 DOI: 10.1016/j.jss.2018.09.076] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 07/26/2018] [Accepted: 09/25/2018] [Indexed: 12/20/2022]
Abstract
BACKGROUND Extracorporeal perfusion is a technique that aims to safely prolong tissue preservation by reducing ischemia-reperfusion injury. Free muscle flaps provide a sensitive research model due to their low ischemic tolerance. However, long-term perfusion of free muscle flaps is scarcely researched. The aim of this study was to compare tissue damage in musculocutaneous flaps during 36 h of extracorporeal perfusion versus static cold storage. MATERIALS AND METHODS Bilateral free rectus abdominis flaps were harvested from five Dutch Landrace pigs (weight: 53-59 kg). Flaps were treated for 36 h according to the following study groups: (1) cold storage at 4°C-6°C (n = 4), (2) perfusion with histidine-tryptophan-ketoglutarate (HTK) at 8°C-10°C (n = 3), (3) perfusion with University of Wisconsin solution (UW) at 8°C-10°C (n = 3). Perfusion fluid samples (creatinine kinase, blood gas) and biopsies for quantitative polymerase chain reaction were collected at multiple time points. Microcirculation was assessed at 24 h of preservation using indocyanine-green fluorescence angiography. Flap weight was measured at the start and end of the preservation period. RESULTS Successful and stable perfusion for 36 h was achieved in all perfused flaps. The mean creatinine kinase increase in the perfusion fluid was comparable in both the groups (UW: +43,144 U/L, HTK: +44,404 U/L). Mean lactate was higher in the UW group than in the HTK group (6.57 versus 1.07 mmol/L). There were homogenous and complete perfusion patterns on indocyanine-green angiography in both the perfusion groups, in contrast to incomplete and inhomogeneous patterns during cold storage. Expression of genes related to apoptosis and inflammation was lower in perfused flaps than in the cold storage group. Weight increase was highest in the HTK group (78%; standard deviation [SD], 29%) compared with UW (22%; SD, 22%) and cold storage (0.7%; SD, 4%). CONCLUSIONS Long-term extracorporeal perfusion of free rectus abdominis flaps is feasible. Outcomes in the perfusion groups seemed superior compared to cold storage. Hypotheses gained from this research need to be further explored in a replantation setting.
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Britto FA, Cortade F, Belloum Y, Blaquière M, Gallot YS, Docquier A, Pagano AF, Jublanc E, Bendridi N, Koechlin-Ramonatxo C, Chabi B, Francaux M, Casas F, Freyssenet D, Rieusset J, Giorgetti-Peraldi S, Carnac G, Ollendorff V, Favier FB. Glucocorticoid-dependent REDD1 expression reduces muscle metabolism to enable adaptation under energetic stress. BMC Biol 2018; 16:65. [PMID: 29895328 PMCID: PMC5998563 DOI: 10.1186/s12915-018-0525-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2018] [Accepted: 05/04/2018] [Indexed: 12/14/2022] Open
Abstract
Background Skeletal muscle atrophy is a common feature of numerous chronic pathologies and is correlated with patient mortality. The REDD1 protein is currently recognized as a negative regulator of muscle mass through inhibition of the Akt/mTORC1 signaling pathway. REDD1 expression is notably induced following glucocorticoid secretion, which is a component of energy stress responses. Results Unexpectedly, we show here that REDD1 instead limits muscle loss during energetic stresses such as hypoxia and fasting by reducing glycogen depletion and AMPK activation. Indeed, we demonstrate that REDD1 is required to decrease O2 and ATP consumption in skeletal muscle via reduction of the extent of mitochondrial-associated endoplasmic reticulum membranes (MAMs), a central hub connecting energy production by mitochondria and anabolic processes. In fact, REDD1 inhibits ATP-demanding processes such as glycogen storage and protein synthesis through disruption of the Akt/Hexokinase II and PRAS40/mTORC1 signaling pathways in MAMs. Our results uncover a new REDD1-dependent mechanism coupling mitochondrial respiration and anabolic processes during hypoxia, fasting, and exercise. Conclusions Therefore, REDD1 is a crucial negative regulator of energy expenditure that is necessary for muscle adaptation during energetic stresses. This present study could shed new light on the role of REDD1 in several pathologies associated with energetic metabolism alteration, such as cancer, diabetes, and Parkinson’s disease. Electronic supplementary material The online version of this article (10.1186/s12915-018-0525-4) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | - Marine Blaquière
- PHYMEDEXP, Univ. Montpellier, INSERM, CNRS, CHRU of Montpellier, Montpellier, France
| | | | | | | | | | - Nadia Bendridi
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1397, Oullins, France
| | | | | | - Marc Francaux
- Institute of Neuroscience, Université catholique de Louvain, Louvain-la-Neuve, Belgium
| | | | | | - Jennifer Rieusset
- INSERM UMR-1060, CarMeN Laboratory, Lyon 1 University, INRA U1397, Oullins, France
| | | | - Gilles Carnac
- PHYMEDEXP, Univ. Montpellier, INSERM, CNRS, CHRU of Montpellier, Montpellier, France
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Tirado-Hurtado I, Fajardo W, Pinto JA. DNA Damage Inducible Transcript 4 Gene: The Switch of the Metabolism as Potential Target in Cancer. Front Oncol 2018; 8:106. [PMID: 29707520 PMCID: PMC5906527 DOI: 10.3389/fonc.2018.00106] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Accepted: 03/26/2018] [Indexed: 12/02/2022] Open
Abstract
DNA damage inducible transcript 4 (DDIT4) gene is expressed under stress situations turning off the metabolic activity triggered by the mammalian target of rapamycin (mTOR). Several in vitro and in vivo works have demonstrated the ability of DDIT4 to generate resistance to cancer therapy. The link between the metabolism suppression and aggressiveness features of cancer cells remains poorly understood since anti-mTOR agents who are part of the repertoire of drugs used for systemic treatment of cancer achieving variable results. Interestingly, the high DDIT4 expression is associated with worse outcomes compared to tumors with low DDIT4 expression, seen in a wide variety of solid and hematological tumors, which suggests the driver role of this gene and provide the basis to target it as part of a new therapeutic strategy. In this review, we highlight our current knowledge about the biology of DDIT4 and its role as a prognostic biomarker, encompassing the motives for the development of target drugs against DDIT4 as a better target than mTOR inhibitors.
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Affiliation(s)
| | - Williams Fajardo
- Escuela de Medicina Humana, Universidad Privada San Juan Bautista, Lima, Peru
| | - Joseph A Pinto
- Unidad de Investigación Básica y Traslacional, Oncosalud-AUNA, Lima, Peru
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Dickinson JM, D'Lugos AC, Mahmood TN, Ormsby JC, Salvo L, Dedmon WL, Patel SH, Katsma MS, Mookadam F, Gonzales RJ, Hale TM, Carroll CC, Angadi SS. Exercise Protects Skeletal Muscle during Chronic Doxorubicin Administration. Med Sci Sports Exerc 2018; 49:2394-2403. [PMID: 28767526 DOI: 10.1249/mss.0000000000001395] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
PURPOSE This study aimed to assess the ability for exercise training performed before and during biweekly doxorubicin (DOX) administration to attenuate adverse effects of DOX on skeletal muscle. We hypothesized that DOX treatment would increase REDD1, impair mammalian target of rapamycin (mTOR) signaling, and reduce muscle fiber size, and that exercise training would attenuate these responses. METHODS Eight-week-old ovariectomized female Sprague-Dawley rats were randomized to one of four treatments: exercise + DOX (Ex-Dox), Ex + vehicle (Ex-Veh), sedentary + DOX (Sed-Dox), and Sed + Veh (Sed-Veh). DOX (4 mg·kg) or vehicle (saline) intraperitoneal injections were performed biweekly for a total of three injections (cumulative dose, 12 mg·kg). Ex animals performed interval exercise (4 × 4 min, 85%-90% V˙O2peak) 5 d·wk starting 1 wk before the first injection and continued throughout study duration. Animals were euthanized ~5 d after the last injection, during which the soleus muscle was dissected and prepared for immunoblot and immunohistochemical analyses. RESULTS REDD1 mRNA and protein were increased only in Sed-Dox (P < 0.05). The phosphorylation of mTOR and 4E-BP1 and MHC I and MHC IIa fiber size were lower in Sed-Dox versus Sed-Veh (P < 0.05). By contrast, REDD1 mRNA and protein, mTOR, 4E-BP1, and MHC I fiber size were not different between Ex-Dox and Ex-Veh (P > 0.05). LC3BI was higher, and the LC3BII/I ratio was lower in Sed-Dox versus Sed-Veh (P < 0.05) but not between Ex-Dox and Ex-Veh (P > 0.05). CONCLUSION These data suggest that DOX may inhibit mTORC1 activity and reduce MHCI and MHCIIa fiber size, potentially through elevated REDD1, and that exercise may provide a therapeutic strategy to preserve skeletal muscle size during chronic DOX treatment.
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Affiliation(s)
- Jared M Dickinson
- 1School of Nutrition and Health Promotion, Healthy Lifestyles Research Center, Exercise Science and Health Promotion, Arizona State University, Phoenix, AZ; 2Department of Physiology, Arizona College of Osteopathic Medicine, Midwestern University, Glendale, AZ; 3Division of Cardiovascular Diseases, Mayo Clinic Hospital, Phoenix, AZ; 4Department of Basic Medical Sciences, College of Medicine-Phoenix, University of Arizona, Phoenix, AZ; and 5Department of Health and Kinesiology, Purdue University, West Lafayette, IN
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Restorative Mechanisms Regulating Protein Balance in Skeletal Muscle During Recovery From Sepsis. Shock 2018; 47:463-473. [PMID: 27749759 DOI: 10.1097/shk.0000000000000762] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Muscle deconditioning is commonly observed in patients surviving sepsis. Little is known regarding the molecular mechanisms regulating muscle protein homeostasis during the recovery or convalescence phase. We adapted a sepsis-recovery mouse model that uses cecal ligation and puncture (CLP), followed 24 h later by cecal resection and antibiotic treatment, to identify putative cellular pathways regulating protein synthesis and breakdown in skeletal muscle. Ten days after CLP, body weight and food consumption did not differ between control and sepsis-recovery mice, but gastrocnemius weight was reduced. During sepsis-recovery, muscle protein synthesis was increased 2-fold and associated with enhanced mTOR kinase activity (4E-BP1 and S6K1 phosphorylation). The sepsis-induced increase in 4E-BP1 was associated with enhanced formation of the eIF4E-eIF4G active cap-dependent complex, while the increased S6K1 was associated with increased phosphorylation of downstream targets S6 and eIF4B. Proximal to mTOR, sepsis-recovery increased Akt and TSC2 phosphorylation, did not alter AMPK phosphorylation, and decreased REDD1 protein content. Despite the decreased mRNA content for the E3 ubiquitin ligases atrogin-1 and muscle RING-finger 1, proteasomal activity was increased 50%. In contrast, sepsis-recovery was associated with an apparent decrease in autophagy (e.g., increased ULK-1 phosphorylation, decreased LCB3-II, and increased p62). The mRNA content for IL-1β, IL-18, TNFα, and IL-6 in muscle was elevated in sepsis-recovery. During recovery after sepsis skeletal muscle responds with an increase in Akt-TSC2-mTOR-dependent protein synthesis and decreased autophagy, but full restoration of muscle protein content may be slowed by the continued stimulation of ubiquitin-proteasome activity.
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Etoposide-induced DNA damage affects multiple cellular pathways in addition to DNA damage response. Oncotarget 2018; 9:24122-24139. [PMID: 29844877 PMCID: PMC5963631 DOI: 10.18632/oncotarget.24517] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2017] [Accepted: 02/10/2018] [Indexed: 02/06/2023] Open
Abstract
DNA damage response (DDR) coordinates lesion repair and checkpoint activation. DDR is intimately connected with transcription. However, the relationship between DDR and transcription has not been clearly established. We report here RNA-sequencing analyses of MCF7 cells containing double-strand breaks induced by etoposide. While etoposide does not apparently cause global changes in mRNA abundance, it altered some gene expression. At the setting of fold alteration ≥ 2 and false discovery rate (FDR) ≤ 0.001, FDR < 0.05, or p < 0.05, etoposide upregulated 96, 268, or 860 genes and downregulated 41, 133, or 503 genes in MCF7 cells. Among these differentially expressed genes (DEGs), the processes of biogenesis, metabolism, cell motility, signal transduction, and others were affected; the pathways of Ras GTPase activity, RNA binding, cytokine-mediated signaling, kinase regulatory activity, protein binding, and translation were upregulated, and those pathways related to coated vesicle, calmodulin binding, and microtubule-based movement were downregulated. We further identified RABL6, RFTN2, FAS-AS1, and TCEB3CL as new DDR-affected genes in MCF7 and T47D cells. By metabolic labelling using 4-thiouridine, we observed dynamic alterations in the transcription of these genes in etoposide-treated MCF7 and T47D cells. During 0-2 hour etoposide treatment, RABL6 transcription was robustly increased at 0.5 and 1 hour in MCF7 cells and at 2 hours in T47D cells, while FAS-AS1 transcription was dramatically and steadily elevated in both cell lines. Taken together, we demonstrate dynamic alterations in transcription and that these changes affect multiple cellular processes in etoposide-induced DDR.
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Gordon BS, Steiner JL, Rossetti ML, Qiao S, Ellisen LW, Govindarajan SS, Eroshkin AM, Williamson DL, Coen PM. REDD1 induction regulates the skeletal muscle gene expression signature following acute aerobic exercise. Am J Physiol Endocrinol Metab 2017; 313:E737-E747. [PMID: 28899858 PMCID: PMC5814598 DOI: 10.1152/ajpendo.00120.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Revised: 08/08/2017] [Accepted: 09/04/2017] [Indexed: 11/22/2022]
Abstract
The metabolic stress placed on skeletal muscle by aerobic exercise promotes acute and long-term health benefits in part through changes in gene expression. However, the transducers that mediate altered gene expression signatures have not been completely elucidated. Regulated in development and DNA damage 1 (REDD1) is a stress-induced protein whose expression is transiently increased in skeletal muscle following acute aerobic exercise. However, the role of this induction remains unclear. Because REDD1 altered gene expression in other model systems, we sought to determine whether REDD1 induction following acute exercise altered the gene expression signature in muscle. To do this, wild-type and REDD1-null mice were randomized to remain sedentary or undergo a bout of acute treadmill exercise. Exercised mice recovered for 1, 3, or 6 h before euthanization. Acute exercise induced a transient increase in REDD1 protein expression within the plantaris only at 1 h postexercise, and the induction occurred in both cytosolic and nuclear fractions. At this time point, global changes in gene expression were surveyed using microarray. REDD1 induction was required for the exercise-induced change in expression of 24 genes. Validation by RT-PCR confirmed that the exercise-mediated changes in genes related to exercise capacity, muscle protein metabolism, neuromuscular junction remodeling, and Metformin action were negated in REDD1-null mice. Finally, the exercise-mediated induction of REDD1 was partially dependent upon glucocorticoid receptor activation. In all, these data show that REDD1 induction regulates the exercise-mediated change in a distinct set of genes within skeletal muscle.
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Affiliation(s)
- Bradley S Gordon
- Department of Nutrition, Food, and Exercise Science, Florida State University, Tallahassee, Florida;
- Institute of Exercise Physiology and Wellness, University of Central Florida, Orlando, Florida
| | - Jennifer L Steiner
- Department of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, Pennsylvania
| | - Michael L Rossetti
- Department of Nutrition, Food, and Exercise Science, Florida State University, Tallahassee, Florida
- Institute of Exercise Physiology and Wellness, University of Central Florida, Orlando, Florida
| | - Shuxi Qiao
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
| | - Leif W Ellisen
- Massachusetts General Hospital Cancer Center, Boston, Massachusetts
- Harvard Medical School, Boston, Massachusetts
| | | | - Alexey M Eroshkin
- Sanford Burnham Prebys Medical Discovery Institute, La Jolla, California
| | - David L Williamson
- Kinesiology Program, School of Behavioral Sciences and Education, Pennsylvania State University-Harrisburg, Middletown, Pennsylvania; and
| | - Paul M Coen
- Sanford Burnham Prebys Medical Discovery Institute, Orlando, Florida
- Translational Research Institute for Metabolism and Diabetes, Florida Hospital, Orlando, Florida
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Ogasawara R, Arihara Y, Takegaki J, Nakazato K, Ishii N. Relationship between exercise volume and muscle protein synthesis in a rat model of resistance exercise. J Appl Physiol (1985) 2017; 123:710-716. [DOI: 10.1152/japplphysiol.01009.2016] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 07/17/2017] [Accepted: 07/17/2017] [Indexed: 01/17/2023] Open
Abstract
Resistance exercise (RE) volume is recognized as an important factor that stimulates muscle protein synthesis (MPS) and is considered, at least in part, to be involved in the mammalian target of rapamycin complex 1 (mTORC1)-associated signaling. However, the effects of relatively high-volume RE on mTORC1 and MPS remain unclear. In the present study, we used an animal model of RE to investigate the relationship between RE volume and MPS. Male Sprague-Dawley rats were subjected to RE, and muscle samples were obtained 6 h after performing 1, 3, 5, 10, or 20 sets of RE. Although 1 set of RE did not increase MPS [measured by the surface sensing of translation (SUnSET) method], multiple sets (3, 5, 10, and 20 sets) significantly increased MPS. However, the increase in MPS reached a plateau after 3 or 5 sets of RE, and no further increase in MPS was observed with additional RE sets. In contrast to the MPS response, we observed that p70S6K phosphorylation at Thr389, a marker of mTORC1 activity, and Ser240/244 phosphorylation of rpS6, a downstream target of p70S6K, gradually increased with higher RE volume. The above results suggest that the relationship between RE volume and MPS was not linear. Thus the increase in MPS with increasing RE volume saturates before p70S6K phosphorylation, suggesting a threshold effect for the relationship between p70S6K activation and MPS. NEW & NOTEWORTHY The aim of this study was to investigate the relationship between resistance exercise (RE) volume and muscle protein synthesis. We found that the relationship between RE volume and p70S6K phosphorylation was almost linear, but the increase in muscle protein synthesis began to plateau after approximately five sets of RE.
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Affiliation(s)
- Riki Ogasawara
- Department of Life Science and Applied Chemistry, Nagoya Institute of Technology, Nagoya, Japan
- Department of Life Sciences, The University of Tokyo, Tokyo, Japan; and
| | - Yuki Arihara
- Department of Life Sciences, The University of Tokyo, Tokyo, Japan; and
| | - Junya Takegaki
- Department of Life Sciences, The University of Tokyo, Tokyo, Japan; and
| | - Koichi Nakazato
- Department of Exercise Physiology, Nippon Sport Science University, Tokyo, Japan
| | - Naokata Ishii
- Department of Life Sciences, The University of Tokyo, Tokyo, Japan; and
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Wong HR, Cvijanovich NZ, Anas N, Allen GL, Thomas NJ, Bigham MT, Weiss SL, Fitzgerald JC, Checchia PA, Meyer K, Quasney M, Hall M, Gedeit R, Freishtat RJ, Nowak J, Raj SS, Gertz S, Grunwell JR, Lindsell CJ. Improved Risk Stratification in Pediatric Septic Shock Using Both Protein and mRNA Biomarkers. PERSEVERE-XP. Am J Respir Crit Care Med 2017; 196:494-501. [PMID: 28324661 DOI: 10.1164/rccm.201701-0066oc] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
RATIONALE We previously derived and validated the Pediatric Sepsis Biomarker Risk Model (PERSEVERE) to estimate baseline mortality risk in children with septic shock. The PERSEVERE biomarkers are serum proteins selected from among the proteins directly related to 80 mortality risk assessment genes. The initial approach to selecting the PERSEVERE biomarkers left 68 genes unconsidered. OBJECTIVES To determine if the 68 previously unconsidered genes can improve upon the performance of PERSEVERE and to provide biological information regarding the pathophysiology of septic shock. METHODS We reduced the number of variables by determining the biological linkage of the 68 previously unconsidered genes. The genes identified through variable reduction were combined with the PERSEVERE-based mortality probability to derive a risk stratification model for 28-day mortality using classification and regression tree methodology (n = 307). The derived tree, PERSEVERE-XP, was then tested in a separate cohort (n = 77). MEASUREMENTS AND MAIN RESULTS Variable reduction revealed a network consisting of 18 mortality risk assessment genes related to tumor protein 53 (TP53). In the derivation cohort, PERSEVERE-XP had an area under the receiver operating characteristic curve (AUC) of 0.90 (95% confidence interval, 0.85-0.95) for differentiating between survivors and nonsurvivors. In the test cohort, the AUC was 0.96 (95% confidence interval, 0.91-1.0). The AUC of PERSEVERE-XP was superior to that of PERSEVERE. CONCLUSIONS PERSEVERE-XP combines protein and mRNA biomarkers to provide mortality risk stratification with possible clinical utility. PERSEVERE-XP significantly improves on PERSEVERE and suggests a role for TP53-related cellular division, repair, and metabolism in the pathophysiology of septic shock.
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Affiliation(s)
- Hector R Wong
- 1 Division of Critical Care Medicine, Cincinnati Children's Hospital Medical Center and Cincinnati Children's Research Foundation, Cincinnati, Ohio.,2 Department of Pediatrics and
| | | | - Nick Anas
- 4 Children's Hospital of Orange County, Orange, California
| | | | - Neal J Thomas
- 6 Penn State Children's Hospital, Hershey, Pennsylvania
| | | | - Scott L Weiss
- 8 The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | | | - Paul A Checchia
- 9 Texas Children's Hospital and Baylor College of Medicine, Houston, Texas
| | - Keith Meyer
- 10 Miami Children's Hospital, Miami, Florida
| | - Michael Quasney
- 11 C. S. Mott Children's Hospital at the University of Michigan, Ann Arbor, Michigan
| | - Mark Hall
- 12 Nationwide Children's Hospital, Columbus, Ohio
| | - Rainer Gedeit
- 13 Children's Hospital of Wisconsin, Milwaukee, Wisconsin
| | | | - Jeffrey Nowak
- 15 Children's Hospitals and Clinics of Minnesota, Minneapolis, Minnesota
| | - Shekhar S Raj
- 16 Riley Hospital for Children, Indianapolis, Indiana
| | - Shira Gertz
- 17 Joseph M. Sanzari Children's Hospital, Hackensack University Medical Center, Hackensack, New Jersey; and
| | | | - Christopher J Lindsell
- 19 Department of Emergency Medicine, University of Cincinnati College of Medicine, Cincinnati, Ohio
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Amino acid homeostasis and signalling in mammalian cells and organisms. Biochem J 2017; 474:1935-1963. [PMID: 28546457 PMCID: PMC5444488 DOI: 10.1042/bcj20160822] [Citation(s) in RCA: 306] [Impact Index Per Article: 43.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/08/2017] [Accepted: 03/10/2017] [Indexed: 12/19/2022]
Abstract
Cells have a constant turnover of proteins that recycle most amino acids over time. Net loss is mainly due to amino acid oxidation. Homeostasis is achieved through exchange of essential amino acids with non-essential amino acids and the transfer of amino groups from oxidised amino acids to amino acid biosynthesis. This homeostatic condition is maintained through an active mTORC1 complex. Under amino acid depletion, mTORC1 is inactivated. This increases the breakdown of cellular proteins through autophagy and reduces protein biosynthesis. The general control non-derepressable 2/ATF4 pathway may be activated in addition, resulting in transcription of genes involved in amino acid transport and biosynthesis of non-essential amino acids. Metabolism is autoregulated to minimise oxidation of amino acids. Systemic amino acid levels are also tightly regulated. Food intake briefly increases plasma amino acid levels, which stimulates insulin release and mTOR-dependent protein synthesis in muscle. Excess amino acids are oxidised, resulting in increased urea production. Short-term fasting does not result in depletion of plasma amino acids due to reduced protein synthesis and the onset of autophagy. Owing to the fact that half of all amino acids are essential, reduction in protein synthesis and amino acid oxidation are the only two measures to reduce amino acid demand. Long-term malnutrition causes depletion of plasma amino acids. The CNS appears to generate a protein-specific response upon amino acid depletion, resulting in avoidance of an inadequate diet. High protein levels, in contrast, contribute together with other nutrients to a reduction in food intake.
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Graber TG, Borack MS, Reidy PT, Volpi E, Rasmussen BB. Essential amino acid ingestion alters expression of genes associated with amino acid sensing, transport, and mTORC1 regulation in human skeletal muscle. Nutr Metab (Lond) 2017; 14:35. [PMID: 28503190 PMCID: PMC5426042 DOI: 10.1186/s12986-017-0187-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 05/01/2017] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND Amino acid availability stimulates protein synthesis via the mTORC1 (mechanistic target of rapamycin complex 1) signaling pathway. In response to an increase in cellular amino acid availability, translocation of cytosolic mTORC1 to the lysosomal surface is required to stimulate mTORC1 kinase activity. However, research elucidating the amino acid responsive mechanisms have thus far only been conducted in in vitro models. Our primary objective was to determine whether an increase in amino acid availability within human skeletal muscle in vivo would alter the expression of genes associated with amino acid sensing, transport and mTORC1 regulation. Our secondary objective was to determine whether an acute perturbation in lysosomal function would disrupt the normal pattern of muscle amino acid responsive gene expression. METHODS We recruited 13 young adults into one of two groups: The first group ingested 10 g of essential amino acids (EAA). The second group ingested 10 g of EAA in the presence of chloroquine (CQ), a lysosomotropic agent. The subjects from each group had biopsies of the vastus lateralis taken before and after EAA ingestion. We determined the relative mRNA expression of 51 potential amino acid responsive genes using RT-qPCR. RESULTS There was a differential mRNA expression for 22 genes, with 15 mRNAs significantly changing (P < 0.05) in response to EAA ingestion (e.g., REDD1: +209 ± 35%; SLC38A9: +31 ± 9%; SLC38A10: +57 ± 15%). In the CQ group, EAA ingestion resulted in a differential expression as compared to EAA alone (i.e., 11 out of the 22 genes were different (P < 0.05) between the two groups.). CONCLUSIONS Expression of several amino acid sensing, transport, and mTORC1 regulatory genes in human skeletal muscle are responsive to an increase in amino acid availability. Furthermore, potential acute disruption of lysosomal function by ingestion of chloroquine interferes with the normal pattern of gene expression following feeding. Our in vivo data in humans provide preliminary support for the in vitro work linking amino acid sensing pathways to mTORC1 translocation to the lysosome. TRIAL REGISTRATION NCT00891696. Registered 29 April 2009.
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Affiliation(s)
- Ted G. Graber
- Division of Rehabilitation Sciences, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555-1124 USA
| | - Michael S. Borack
- Division of Rehabilitation Sciences, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555-1124 USA
| | - Paul T. Reidy
- Division of Rehabilitation Sciences, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555-1124 USA
- Present Address: Department of Physical Therapy, University of Utah, Salt Lake City, Utah USA
| | - Elena Volpi
- Department of Internal Medicine – Geriatrics, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555-1124 USA
| | - Blake B. Rasmussen
- Department of Nutrition and Metabolism, University of Texas Medical Branch, 301 University Blvd, Galveston, TX 77555-1124 USA
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