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Monteyne AJ, West S, Stephens FB, Wall BT. Reconsidering the pre-eminence of dietary leucine and plasma leucinemia for predicting the stimulation of postprandial muscle protein synthesis rates. Am J Clin Nutr 2024; 120:7-16. [PMID: 38705358 PMCID: PMC11251220 DOI: 10.1016/j.ajcnut.2024.04.032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2023] [Revised: 04/22/2024] [Accepted: 04/29/2024] [Indexed: 05/07/2024] Open
Abstract
The regulation of postprandial muscle protein synthesis (MPS) with or without physical activity has been an intensely studied area within nutrition and physiology. The leucine content of dietary protein and the subsequent plasma leucinemia it elicits postingestion is often considered the primary drivers of the postprandial MPS response. This concept, generally known as the leucine "trigger" hypothesis, has also been adopted within more applied aspects of nutrition. Our view is that recent evidence is driving a more nuanced picture of the regulation of postprandial MPS by revealing a compelling dissociation between ingested leucine or plasma leucinemia and the magnitude of the postprandial MPS response. Much of this lack of coherence has arisen as experimental progress has demanded relevant studies move beyond reliance on isolated amino acids and proteins to use increasingly complex protein-rich meals, whole foods, and mixed meals. Our overreliance on the centrality of leucine in this field has been reflected in 2 recent systematic reviews. In this perspective, we propose a re-evaluation of the pre-eminent role of these leucine variables in the stimulation of postprandial MPS. We view the development of a more complex intellectual framework now a priority if we are to see continued progress concerning the mechanistic regulation of postprandial muscle protein turnover, but also consequential from an applied perspective when evaluating the value of novel dietary protein sources.
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Affiliation(s)
- Alistair J Monteyne
- Department of Sport and Health Sciences, Nutritional Physiology Research Group, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Sam West
- Department of Sport and Health Sciences, Nutritional Physiology Research Group, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Francis B Stephens
- Department of Sport and Health Sciences, Nutritional Physiology Research Group, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom
| | - Benjamin T Wall
- Department of Sport and Health Sciences, Nutritional Physiology Research Group, College of Life and Environmental Sciences, University of Exeter, Exeter, United Kingdom.
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2
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Chen Q, Zhou S, Qu M, Yang Y, Chen Q, Meng X, Fan H. Cucumber (Cucumis sativus L.) translationally controlled tumor protein interacts with CsRab11A and promotes activation of target of rapamycin in response to Podosphaera xanthii. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2024; 119:332-347. [PMID: 38700955 DOI: 10.1111/tpj.16766] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/07/2023] [Revised: 03/12/2024] [Accepted: 03/26/2024] [Indexed: 05/05/2024]
Abstract
The target of rapamycin (TOR) kinase serves as a central regulator that integrates nutrient and energy signals to orchestrate cellular and organismal physiology in both animals and plants. Despite significant advancements having been made in understanding the molecular and cellular functions of plant TOR kinases, the upstream regulators that modulate TOR activity are not yet fully elucidated. In animals, the translationally controlled tumor protein (TCTP) is recognized as a key player in TOR signaling. This study reveals that two TCTP isoforms from Cucumis sativus, when introduced into Arabidopsis, are instrumental in balancing growth and defense mechanisms against the fungal pathogen Golovinomyces cichoracearum. We hypothesize that plant TCTPs act as upstream regulators of TOR in response to powdery mildew caused by Podosphaera xanthii in Cucumis. Our research further uncovers a stable interaction between CsTCTP and a small GTPase, CsRab11A. Transient transformation assays indicate that CsRab11A is involved in the defense against P. xanthii and promotes the activation of TOR signaling through CsTCTP. Moreover, our findings demonstrate that the critical role of TOR in plant disease resistance is contingent upon its regulated activity; pretreatment with a TOR inhibitor (AZD-8055) enhances cucumber plant resistance to P. xanthii, while pretreatment with a TOR activator (MHY-1485) increases susceptibility. These results suggest a sophisticated adaptive response mechanism in which upstream regulators, CsTCTP and CsRab11A, coordinate to modulate TOR function in response to P. xanthii, highlighting a novel aspect of plant-pathogen interactions.
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Affiliation(s)
- Qiumin Chen
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, China
| | - Shuang Zhou
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, China
| | - Mengqi Qu
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, China
| | - Yun Yang
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, China
| | - Qinglei Chen
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, China
| | - Xiangnan Meng
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, China
- Key Laboratory of Agricultural Biotechnology of Liaoning Province, Shenyang Agricultural University, Shenyang, China
| | - Haiyan Fan
- College of Bioscience and Biotechnology, Shenyang Agricultural University, Shenyang, China
- Key Laboratory of Protected Horticulture of Ministry of Education, Shenyang Agricultural University, Shenyang, China
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3
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Fujii F, Kanemasa H, Okuzono S, Setoyama D, Taira R, Yonemoto K, Motomura Y, Kato H, Masuda K, Kato TA, Ohga S, Sakai Y. ATP1A3 regulates protein synthesis for mitochondrial stability under heat stress. Dis Model Mech 2024; 17:dmm050574. [PMID: 38804677 PMCID: PMC11247502 DOI: 10.1242/dmm.050574] [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: 11/02/2023] [Accepted: 05/20/2024] [Indexed: 05/29/2024] Open
Abstract
Pathogenic variants in ATP1A3, the gene encoding the α3 subunit of the Na+/K+-ATPase, cause alternating hemiplegia of childhood (AHC) and related disorders. Impairments in Na+/K+-ATPase activity are associated with the clinical phenotype. However, it remains unclear whether additional mechanisms are involved in the exaggerated symptoms under stressed conditions in patients with AHC. We herein report that the intracellular loop (ICL) of ATP1A3 interacted with RNA-binding proteins, such as Eif4g (encoded by Eif4g1), Pabpc1 and Fmrp (encoded by Fmr1), in mouse Neuro2a cells. Both the siRNA-mediated depletion of Atp1a3 and ectopic expression of the p.R756C variant of human ATP1A3-ICL in Neuro2a cells resulted in excessive phosphorylation of ribosomal protein S6 (encoded by Rps6) and increased susceptibility to heat stress. In agreement with these findings, induced pluripotent stem cells (iPSCs) from a patient with the p.R756C variant were more vulnerable to heat stress than control iPSCs. Neurons established from the patient-derived iPSCs showed lower calcium influxes in responses to stimulation with ATP than those in control iPSCs. These data indicate that inefficient protein synthesis contributes to the progressive and deteriorating phenotypes in patients with the p.R756C variant among a variety of ATP1A3-related disorders.
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Affiliation(s)
- Fumihiko Fujii
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Hikaru Kanemasa
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Sayaka Okuzono
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Daiki Setoyama
- Department of Clinical Chemistry and Laboratory Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Ryoji Taira
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Kousuke Yonemoto
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Yoshitomo Motomura
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Hiroki Kato
- Department of Molecular Cell Biology and Oral Anatomy, Graduate School of Dental Science, Kyushu University, Fukuoka, 812-8582, Japan
| | - Keiji Masuda
- Section of Oral Medicine for Children, Division of Oral Health, Growth and Development, Faculty of Dental Science, Kyushu University, Fukuoka, 812-8582, Japan
| | - Takahiro A. Kato
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Shouichi Ohga
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Yasunari Sakai
- Department of Pediatrics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
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Millward DJ. Post-natal muscle growth and protein turnover: a narrative review of current understanding. Nutr Res Rev 2024; 37:141-168. [PMID: 37395180 DOI: 10.1017/s0954422423000124] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
A model explaining the dietary-protein-driven post-natal skeletal muscle growth and protein turnover in the rat is updated, and the mechanisms involved are described, in this narrative review. Dietary protein controls both bone length and muscle growth, which are interrelated through mechanotransduction mechanisms with muscle growth induced both from stretching subsequent to bone length growth and from internal work against gravity. This induces satellite cell activation, myogenesis and remodelling of the extracellular matrix, establishing a growth capacity for myofibre length and cross-sectional area. Protein deposition within this capacity is enabled by adequate dietary protein and other key nutrients. After briefly reviewing the experimental animal origins of the growth model, key concepts and processes important for growth are reviewed. These include the growth in number and size of the myonuclear domain, satellite cell activity during post-natal development and the autocrine/paracrine action of IGF-1. Regulatory and signalling pathways reviewed include developmental mechanotransduction, signalling through the insulin/IGF-1-PI3K-Akt and the Ras-MAPK pathways in the myofibre and during mechanotransduction of satellite cells. Likely pathways activated by maximal-intensity muscle contractions are highlighted and the regulation of the capacity for protein synthesis in terms of ribosome assembly and the translational regulation of 5-TOPmRNA classes by mTORC1 and LARP1 are discussed. Evidence for and potential mechanisms by which volume limitation of muscle growth can occur which would limit protein deposition within the myofibre are reviewed. An understanding of how muscle growth is achieved allows better nutritional management of its growth in health and disease.
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Affiliation(s)
- D Joe Millward
- Department of Nutritional Sciences, School of Biosciences & Medicine, Faculty of Health and Medical Sciences, University of Surrey, Guildford, UK
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Hannaian SJ, Lov J, Cheng-Boivin Z, Abou Sawan S, Hodson N, Gentil BJ, Morais JA, Churchward-Venne TA. Acute effects of a ketone monoester, whey protein, or their coingestion on mTOR trafficking and protein-protein colocalization in human skeletal muscle. Am J Physiol Cell Physiol 2024; 326:C1769-C1775. [PMID: 38682238 DOI: 10.1152/ajpcell.00207.2024] [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: 03/28/2024] [Revised: 04/22/2024] [Accepted: 04/22/2024] [Indexed: 05/01/2024]
Abstract
We recently demonstrated that acute oral ketone monoester intake induces a stimulation of postprandial myofibrillar protein synthesis rates comparable to that elicited following the ingestion of 10 g whey protein or their coingestion. The present investigation aimed to determine the acute effects of ingesting a ketone monoester, whey protein, or their coingestion on mechanistic target of rapamycin (mTOR)-related protein-protein colocalization and intracellular trafficking in human skeletal muscle. In a randomized, double-blind, parallel group design, 36 healthy recreationally active young males (age: 24.2 ± 4.1 yr) ingested either: 1) 0.36 g·kg-1 bodyweight of the ketone monoester (R)-3-hydroxybutyl (R)-3-hydroxybutyrate (KET), 2) 10 g whey protein (PRO), or 3) the combination of both (KET + PRO). Muscle biopsies were obtained in the overnight postabsorptive state (basal conditions), and at 120 and 300 min in the postprandial period for immunofluorescence assessment of protein translocation and colocalization of mTOR-related signaling molecules. All treatments resulted in a significant (Interaction: P < 0.0001) decrease in tuberous sclerosis complex 2 (TSC2)-Ras homolog enriched in brain (Rheb) colocalization at 120 min versus basal; however, the decrease was sustained at 300 min versus basal (P < 0.0001) only in KET + PRO. PRO and KET + PRO increased (Interaction: P < 0.0001) mTOR-Rheb colocalization at 120 min versus basal; however, KET + PRO resulted in a sustained increase in mTOR-Rheb colocalization at 300 min that was greater than KET and PRO. Treatment intake increased mTOR-wheat germ agglutinin (WGA) colocalization at 120 and 300 min (Time: P = 0.0031), suggesting translocation toward the fiber periphery. These findings demonstrate that ketone monoester intake can influence the spatial mechanisms involved in the regulation of mTORC1 in human skeletal muscle.NEW & NOTEWORTHY We explored the effects of a ketone monoester (KET), whey protein (PRO), or their coingestion (KET + PRO) on mTOR-related protein-protein colocalization and intracellular trafficking in human muscle. All treatments decreased TSC2-Rheb colocalization at 120 minutes; however, KET + PRO sustained the decrease at 300 min. Only PRO and KET + PRO increased mTOR-Rheb colocalization; however, the increase at 300 min was greater in KET + PRO. Treatment intake increased mTOR-WGA colocalization, suggesting translocation to the fiber periphery. Ketone bodies influence the spatial regulation of mTOR.
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Affiliation(s)
- Sarkis J Hannaian
- Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
| | - Jamie Lov
- Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada
| | - Zacharie Cheng-Boivin
- Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada
| | | | - Nathan Hodson
- Department of Sport and Exercise Science, Institute of Sport, Manchester Metropolitan University, Manchester, United Kingdom
| | - Benoit J Gentil
- Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
| | - José A Morais
- Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
- Department of Medicine, Division of Geriatric Medicine, McGill University, Montreal, Quebec, Canada
| | - Tyler A Churchward-Venne
- Department of Kinesiology and Physical Education, McGill University, Montreal, Quebec, Canada
- Research Institute of the McGill University Health Centre, Montreal, Quebec, Canada
- Department of Medicine, Division of Geriatric Medicine, McGill University, Montreal, Quebec, Canada
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6
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Xie PL, Zheng MY, Han R, Chen WX, Mao JH. Pharmacological mTOR inhibitors in ameliorating Alzheimer's disease: current review and perspectives. Front Pharmacol 2024; 15:1366061. [PMID: 38873415 PMCID: PMC11169825 DOI: 10.3389/fphar.2024.1366061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 04/25/2024] [Indexed: 06/15/2024] Open
Abstract
Traditionally, pharmacological mammalian/mechanistic targets of rapamycin (mTOR) kinase inhibitors have been used during transplantation and tumor treatment. Emerging pre-clinical evidence from the last decade displayed the surprising effectiveness of mTOR inhibitors in ameliorating Alzheimer's Disease (AD), a common neurodegenerative disorder characterized by progressive cognitive function decline and memory loss. Research shows mTOR activation as an early event in AD development, and inhibiting mTOR may promote the resolution of many hallmarks of Alzheimer's. Aberrant protein aggregation, including amyloid-beta (Aβ) deposition and tau filaments, and cognitive defects, are reversed upon mTOR inhibition. A closer inspection of the evidence highlighted a temporal dependence and a hallmark-specific nature of such beneficial effects. Time of administration relative to disease progression, and a maintenance of a functional lysosomal system, could modulate its effectiveness. Moreover, mTOR inhibition also exerts distinct effects between neurons, glial cells, and endothelial cells. Different pharmacological properties of the inhibitors also produce different effects based on different blood-brain barrier (BBB) entry capacities and mTOR inhibition sites. This questions the effectiveness of mTOR inhibition as a viable AD intervention strategy. In this review, we first summarize the different mTOR inhibitors available and their characteristics. We then comprehensively update and discuss the pre-clinical results of mTOR inhibition to resolve many of the hallmarks of AD. Key pathologies discussed include Aβ deposition, tauopathies, aberrant neuroinflammation, and neurovascular system breakdowns.
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Affiliation(s)
- Pei-Lun Xie
- University College London, London, United Kingdom
| | | | - Ran Han
- Dongfang Hospital of Beijing University of Chinese Medicine, Beijing, China
| | - Wei-Xin Chen
- Dongfang Hospital of Beijing University of Chinese Medicine, Beijing, China
| | - Jin-Hua Mao
- Beijing University of Chinese Medicine, Beijing, China
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7
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Castillo-Velasquez C, Matamala E, Becerra D, Orio P, Brauchi SE. Optical recordings of organellar membrane potentials and the components of membrane conductance in lysosomes. J Physiol 2024; 602:1637-1654. [PMID: 38625711 DOI: 10.1113/jp283825] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Accepted: 03/20/2024] [Indexed: 04/17/2024] Open
Abstract
The eukaryotic cell is highly compartmentalized with organelles. Owing to their function in transporting metabolites, metabolic intermediates and byproducts of metabolic activity, organelles are important players in the orchestration of cellular function. Recent advances in optical methods for interrogating the different aspects of organellar activity promise to revolutionize our ability to dissect cellular processes with unprecedented detail. The transport activity of organelles is usually coupled to the transport of charged species; therefore, it is not only associated with the metabolic landscape but also entangled with membrane potentials. In this context, the targeted expression of fluorescent probes for interrogating organellar membrane potential (Ψorg) emerges as a powerful approach, offering less-invasive conditions and technical simplicity to interrogate cellular signalling and metabolism. Different research groups have made remarkable progress in adapting a variety of optical methods for measuring and monitoring Ψorg. These approaches include using potentiometric dyes, genetically encoded voltage indicators, hybrid fluorescence resonance energy transfer sensors and photoinduced electron transfer systems. These studies have provided consistent values for the resting potential of single-membrane organelles, such as lysosomes, the Golgi and the endoplasmic reticulum. We can foresee the use of dynamic measurements of Ψorg to study fundamental problems in organellar physiology that are linked to serious cellular disorders. Here, we present an overview of the available techniques, a survey of the resting membrane potential of internal membranes and, finally, an open-source mathematical model useful to interpret and interrogate membrane-bound structures of small volume by using the lysosome as an example.
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Affiliation(s)
- Cristian Castillo-Velasquez
- Department of Physiology, Faculty of Medicine, Universidad Austral de Chile, Valdivia, Chile
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Valdivia, Chile
| | - Ella Matamala
- Department of Physiology, Faculty of Medicine, Universidad Austral de Chile, Valdivia, Chile
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Valdivia, Chile
| | - Diego Becerra
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
| | - Patricio Orio
- Centro Interdisciplinario de Neurociencia de Valparaíso, Universidad de Valparaíso, Valparaíso, Chile
- Instituto de Neurociencias, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Sebastian E Brauchi
- Department of Physiology, Faculty of Medicine, Universidad Austral de Chile, Valdivia, Chile
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Valdivia, Chile
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Caligaris M, De Virgilio C. Proxies introduce bias in decoding TORC1 activity. MICROPUBLICATION BIOLOGY 2024; 2024:10.17912/micropub.biology.001170. [PMID: 38605723 PMCID: PMC11007552 DOI: 10.17912/micropub.biology.001170] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/22/2024] [Accepted: 03/25/2024] [Indexed: 04/13/2024]
Abstract
The eukaryotic TORC1 kinase integrates and links nutritional, energy, and hormonal signals to cell growth and homeostasis, and its deregulation is associated with human diseases including neurodegeneration, cancer, and metabolic syndrome. Quantification of TORC1 activities in various genetic settings and defined physiological conditions generally relies on the assessment of the phosphorylation level of residues in TORC1 targets. Here we show that two commonly used TORC1 effectors in yeast, namely Sch9 and Rps6, exhibit distinct phosphorylation patterns in response to rapamycin treatment or changes in nitrogen availability, indicating that the choice of TORC1 proxies introduces a bias in decoding TORC1 activity.
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Affiliation(s)
- Marco Caligaris
- Department of Biology, University of Fribourg, Fribourg, Fribourg, Switzerland
| | - Claudio De Virgilio
- Department of Biology, University of Fribourg, Fribourg, Fribourg, Switzerland
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Chang I, Loo YL, Patel J, Nguyen JT, Kim JK, Krebsbach PH. Targeting of lysosomal-bound protein mEAK-7 for cancer therapy. Front Oncol 2024; 14:1375498. [PMID: 38532930 PMCID: PMC10963491 DOI: 10.3389/fonc.2024.1375498] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2024] [Accepted: 02/29/2024] [Indexed: 03/28/2024] Open
Abstract
mEAK-7 (mammalian EAK-7 or MTOR-associated protein, eak-7 homolog), is an evolutionarily conserved lysosomal membrane protein that is highly expressed in several cancer cells. Multiple recent studies have identified mEAK-7 as a positive activator of mTOR (mammalian/mechanistic target of rapamycin) signaling via an alternative mTOR complex, implying that mEAK-7 plays an important role in the promotion of cancer proliferation and migration. In addition, structural analyses investigating interactions between mEAK-7 and V-ATPase, a protein complex responsible for regulating pH homeostasis in cellular compartments, have suggested that mEAK-7 may contribute to V-ATPase-mediated mTORC1 activation. The C-terminal α-helix of mEAK-7 binds to the D and B subunits of the V-ATPase, creating a pincer-like grip around its B subunit. This binding undergoes partial disruption during ATP hydrolysis, potentially enabling other proteins such as mTOR to bind to the α-helix of mEAK-7. mEAK-7 also promotes chemoresistance and radiation resistance by sustaining DNA damage-mediated mTOR signaling through interactions with DNA-PKcs (DNA-dependent protein kinase catalytic subunit). Taken together, these findings indicate that mEAK-7 may be a promising therapeutic target against tumors. However, the precise molecular mechanisms and signal transduction pathways of mEAK-7 in cancer remain largely unknown, motivating the need for further investigation. Here, we summarize the current known roles of mEAK-7 in normal physiology and cancer development by reviewing the latest studies and discuss potential future developments of mEAK-7 in targeted cancer therapy.
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Affiliation(s)
- Insoon Chang
- Section of Endodontics, Division of Regenerative and Reconstructive Sciences, School of Dentistry, University of California, Los Angeles, Los Angeles, CA, United States
| | - Yi-Ling Loo
- School of Dentistry, University of California, Los Angeles, Los Angeles, CA, United States
| | - Jay Patel
- School of Dentistry, University of California, Los Angeles, Los Angeles, CA, United States
| | - Joe Truong Nguyen
- Laboratory of Cancer Biology and Genetics, National Cancer Institute, National Institutes of Health, Bethesda, MD, United States
- Oral Immunobiology Unit, National Institutes of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, United States
| | - Jin Koo Kim
- Division of Oral and Systemic Health Sciences, School of Dentistry, University of California, Los Angeles, Los Angeles, CA, United States
| | - Paul H Krebsbach
- Division of Oral and Systemic Health Sciences, School of Dentistry, University of California, Los Angeles, Los Angeles, CA, United States
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Yan X, Kuang BH, Ma S, Wang R, Lin J, Zeng YX, Xie X, Feng L. NOP14-mediated ribosome biogenesis is required for mTORC2 activation and predicts rapamycin sensitivity. J Biol Chem 2024; 300:105681. [PMID: 38272224 PMCID: PMC10891341 DOI: 10.1016/j.jbc.2024.105681] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 12/23/2023] [Accepted: 01/08/2024] [Indexed: 01/27/2024] Open
Abstract
The mechanistic target of rapamycin (mTOR) forms two distinct complexes: rapamycin-sensitive mTOR complex 1 (mTORC1) and rapamycin-insensitive mTORC2. mTORC2 primarily regulates cell survival by phosphorylating Akt, though the upstream regulation of mTORC2 remains less well-defined than that of mTORC1. In this study, we show that NOP14, a 40S ribosome biogenesis factor and a target of the mTORC1-S6K axis, plays an essential role in mTORC2 signaling. Knockdown of NOP14 led to mTORC2 inactivation and Akt destabilization. Conversely, overexpression of NOP14 stimulated mTORC2-Akt activation and enhanced cell proliferation. Fractionation and coimmunoprecipitation assays demonstrated that the mTORC2 complex was recruited to the rough endoplasmic reticulum through association with endoplasmic reticulum-bound ribosomes. In vivo, high levels of NOP14 correlated with poor prognosis in multiple cancer types. Notably, cancer cells with NOP14 high expression exhibit increased sensitivity to mTOR inhibitors, because the feedback activation of the PI3K-PDK1-Akt axis by mTORC1 inhibition was compensated by mTORC2 inhibition partly through NOP14 downregulation. In conclusion, our findings reveal a spatial regulation of mTORC2-Akt signaling and identify ribosome biogenesis as a potential biomarker for assessing rapalog response in cancer therapy.
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Affiliation(s)
- Xiao Yan
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, China; School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China
| | - Bo-Hua Kuang
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, China; Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Shengsuo Ma
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Ruihua Wang
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Jinzhong Lin
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, China; Shanghai Institute of Infectious Disease and Biosecurity, Fudan University, Shanghai, China; Zhangjiang mRNA Innovation and Translation Center, Fudan University, Shanghai, China
| | - Yi-Xin Zeng
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, China
| | - Xiaoduo Xie
- School of Medicine, Shenzhen Campus of Sun Yat-sen University, Sun Yat-sen University, Shenzhen, China.
| | - Lin Feng
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, China.
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11
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Shariq M, Khan MF, Raj R, Ahsan N, Kumar P. PRKAA2, MTOR, and TFEB in the regulation of lysosomal damage response and autophagy. J Mol Med (Berl) 2024; 102:287-311. [PMID: 38183492 DOI: 10.1007/s00109-023-02411-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Revised: 12/07/2023] [Accepted: 12/18/2023] [Indexed: 01/08/2024]
Abstract
Lysosomes function as critical signaling hubs that govern essential enzyme complexes. LGALS proteins (LGALS3, LGALS8, and LGALS9) are integral to the endomembrane damage response. If ESCRT fails to rectify damage, LGALS-mediated ubiquitination occurs, recruiting autophagy receptors (CALCOCO2, TRIM16, and SQSTM1) and VCP/p97 complex containing UBXN6, PLAA, and YOD1, initiating selective autophagy. Lysosome replenishment through biogenesis is regulated by TFEB. LGALS3 interacts with TFRC and TRIM16, aiding ESCRT-mediated repair and autophagy-mediated removal of damaged lysosomes. LGALS8 inhibits MTOR and activates TFEB for ATG and lysosomal gene transcription. LGALS9 inhibits USP9X, activates PRKAA2, MAP3K7, ubiquitination, and autophagy. Conjugation of ATG8 to single membranes (CASM) initiates damage repair mediated by ATP6V1A, ATG16L1, ATG12, ATG5, ATG3, and TECPR1. ATG8ylation or CASM activates the MERIT system (ESCRT-mediated repair, autophagy-mediated clearance, MCOLN1 activation, Ca2+ release, RRAG-GTPase regulation, MTOR modulation, TFEB activation, and activation of GTPase IRGM). Annexins ANAX1 and ANAX2 aid damage repair. Stress granules stabilize damaged membranes, recruiting FLCN-FNIP1/2, G3BP1, and NUFIP1 to inhibit MTOR and activate TFEB. Lysosomes coordinate the synergistic response to endomembrane damage and are vital for innate and adaptive immunity. Future research should unveil the collaborative actions of ATG proteins, LGALSs, TRIMs, autophagy receptors, and lysosomal proteins in lysosomal damage response.
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Affiliation(s)
- Mohd Shariq
- Quantlase Imaging Laboratory, Quantlase Lab LLC, Unit 1-8, Masdar City, Abu Dhabi, UAE.
| | - Mohammad Firoz Khan
- Quantlase Imaging Laboratory, Quantlase Lab LLC, Unit 1-8, Masdar City, Abu Dhabi, UAE.
| | - Reshmi Raj
- Quantlase Imaging Laboratory, Quantlase Lab LLC, Unit 1-8, Masdar City, Abu Dhabi, UAE
| | - Nuzhat Ahsan
- Quantlase Imaging Laboratory, Quantlase Lab LLC, Unit 1-8, Masdar City, Abu Dhabi, UAE
| | - Pramod Kumar
- Quantlase Imaging Laboratory, Quantlase Lab LLC, Unit 1-8, Masdar City, Abu Dhabi, UAE
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12
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Chen Y, Han L, Dufour CR, Alfonso A, Giguère V. Canonical and Nuclear mTOR Specify Distinct Transcriptional Programs in Androgen-Dependent Prostate Cancer Cells. Mol Cancer Res 2024; 22:113-124. [PMID: 37889103 DOI: 10.1158/1541-7786.mcr-23-0087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Revised: 09/21/2023] [Accepted: 10/24/2023] [Indexed: 10/28/2023]
Abstract
mTOR is a serine/threonine kinase that controls prostate cancer cell growth in part by regulating gene programs associated with metabolic and cell proliferation pathways. mTOR-mediated control of gene expression can be achieved via phosphorylation of transcription factors, leading to changes in their cellular localization and activities. mTOR also directly associates with chromatin in complex with transcriptional regulators, including the androgen receptor (AR). Nuclear mTOR (nmTOR) has been previously shown to act as a transcriptional integrator of the androgen signaling pathway in association with the chromatin remodeling machinery, AR, and FOXA1. However, the contribution of cytoplasmic mTOR (cmTOR) and nmTOR and the role played by FOXA1 in this process remains to be explored. Herein, we engineered cells expressing mTOR tagged with nuclear localization and export signals dictating mTOR localization. Transcriptome profiling in AR-positive prostate cancer cells revealed that nmTOR generally downregulates a subset of the androgen response pathway independently of its kinase activity, while cmTOR upregulates a cell cycle-related gene signature in a kinase-dependent manner. Biochemical and genome-wide transcriptomic analyses demonstrate that nmTOR functionally interacts with AR and FOXA1. Ablation of FOXA1 reprograms the nmTOR cistrome and transcriptome of androgen responsive prostate cancer cells. This works highlights a transcriptional regulatory pathway in which direct interactions between nmTOR, AR and FOXA1 dictate a combinatorial role for these factors in the control of specific gene programs in prostate cancer cells. IMPLICATIONS The finding that canonical and nuclear mTOR signaling pathways control distinct gene programs opens therapeutic opportunities to modulate mTOR activity in prostate cancer cells.
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Affiliation(s)
- Yonghong Chen
- Goodman Cancer Institute, McGill University, Montréal, Québec, Canada
- Department of Biochemistry, Faculty of Medicine and Health Sciences, McGill University, Montréal, Québec, Canada
| | - Lingwei Han
- Goodman Cancer Institute, McGill University, Montréal, Québec, Canada
- Department of Biochemistry, Faculty of Medicine and Health Sciences, McGill University, Montréal, Québec, Canada
| | | | - Anthony Alfonso
- Goodman Cancer Institute, McGill University, Montréal, Québec, Canada
- Department of Biochemistry, Faculty of Medicine and Health Sciences, McGill University, Montréal, Québec, Canada
| | - Vincent Giguère
- Goodman Cancer Institute, McGill University, Montréal, Québec, Canada
- Department of Biochemistry, Faculty of Medicine and Health Sciences, McGill University, Montréal, Québec, Canada
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13
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Derosa S, Misztak P, Mingardi J, Mazzini G, Müller HK, Musazzi L. Changes in neurotrophic signaling pathways in brain areas of the chronic mild stress rat model of depression as a signature of ketamine fast antidepressant response/non-response. Prog Neuropsychopharmacol Biol Psychiatry 2024; 128:110871. [PMID: 37793481 DOI: 10.1016/j.pnpbp.2023.110871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Revised: 09/25/2023] [Accepted: 10/01/2023] [Indexed: 10/06/2023]
Abstract
Major Depressive Disorder (MDD) is a highly debilitating disorder characterized by a persistent feeling of sadness and anhedonia. Traditional antidepressants have a delayed onset of action and lack of efficacy in up to one third of patients, leading to treatment resistant depression (TRD). Recent years have witnessed a revolutionary treatment of TRD with the introduction of the fast-acting antidepressant ketamine. However, ketamine's mechanisms of action are still poorly understood. Here, we used the chronic mild stress animal model of depression on male rats to investigate the involvement of neurotrophic signaling pathways in stress vulnerability/resilience and fast antidepressant response/non-response to acute subanesthetic ketamine. We performed our analysis on both the hippocampus and the prefrontal cortex, two brain areas implicated in stress-related disorders, considering different subcellular fractions. We measured the activation by phosphorylation of protein kinase B (AKT), extracellular signal-regulated kinases (ERKs), glycogen synthase kinase-3 beta (GSK3 β), mammalian target of rapamycin (mTOR), and eukaryotic elongation factor 2 (eEF2), key effectors in the regulation of neuroplasticity and glutamatergic transmission which were previously associated to ketamine's fast antidepressant effect. We showed here for the first time that both stress and ketamine induced brain area and subcellular fraction specific changes in these pathways. Our study represents the first attempt to identify molecular mechanisms underlying the response/non-response to ketamine in an animal model of depression. This approach could give a crucial contribution to the study of etiopathogenetic mechanisms as well as to the identification of novel targets for the development of innovative therapeutic strategies.
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Affiliation(s)
- Sara Derosa
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Paulina Misztak
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Jessica Mingardi
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Giulia Mazzini
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy
| | - Heidi Kaastrup Müller
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Laura Musazzi
- School of Medicine and Surgery, University of Milano-Bicocca, Monza, Italy.
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14
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Srivastav S, van der Graaf K, Singh P, Utama AB, Meyer MD, McNew JA, Stern M. Atl (atlastin) regulates mTor signaling and autophagy in Drosophila muscle through alteration of the lysosomal network. Autophagy 2024; 20:131-150. [PMID: 37649246 PMCID: PMC10761077 DOI: 10.1080/15548627.2023.2249794] [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: 03/06/2023] [Revised: 08/08/2023] [Accepted: 08/11/2023] [Indexed: 09/01/2023] Open
Abstract
ABBREVIATIONS atl atlastin; ALR autophagic lysosome reformation; ER endoplasmic reticulum; GFP green fluorescent protein; HSP hereditary spastic paraplegia; Lamp1 lysosomal associated membrane protein 1 PolyUB polyubiquitin; RFP red fluorescent protein; spin spinster; mTor mechanistic Target of rapamycin; VCP valosin containing protein.
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Affiliation(s)
| | | | - Pratibha Singh
- Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, USA
| | | | - Matthew D. Meyer
- Shared Equipment Authority, Rice University, Houston, Texas, USA
| | - James A. McNew
- Department of BioSciences, Rice University, Houston, Texas, USA
| | - Michael Stern
- Department of BioSciences, Rice University, Houston, Texas, USA
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15
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Moellmann J, Krueger K, Wong DWL, Klinkhammer BM, Buhl EM, Dehairs J, Swinnen JV, Noels H, Jankowski J, Lebherz C, Boor P, Marx N, Lehrke M. 2,8-Dihydroxyadenine-induced nephropathy causes hexosylceramide accumulation with increased mTOR signaling, reduced levels of protective SirT3 expression and impaired renal mitochondrial function. Biochim Biophys Acta Mol Basis Dis 2024; 1870:166825. [PMID: 37536502 DOI: 10.1016/j.bbadis.2023.166825] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 07/24/2023] [Accepted: 07/26/2023] [Indexed: 08/05/2023]
Abstract
AIM Chronic kidney disease (CKD) is accompanied by increased cardiovascular risk and heart failure (HF). In rodents, 2,8-dihydroxyadenine (DHA)-induced nephropathy is a frequently used CKD model. Cardiac and kidney tubular cells share high energy demand to guarantee constant contractive force of the heart or reabsorption/secretion of primary filtrated molecules and waste products by the kidney. Here we analyze time-dependent mechanisms of kidney damage and cardiac consequences under consideration of energetic pathways with the focus on mitochondrial function and lipid metabolism in mice. METHODS AND RESULTS CKD was induced by alternating dietary adenine supplementation (0.2 % or 0.05 % of adenine) in C57BL/6J mice for 9 weeks. Progressive kidney damage led to reduced creatinine clearance, kidney fibrosis and renal inflammation after 3, 6, and 9 weeks. No difference in cardiac function, mitochondrial respiration nor left ventricular fibrosis was observed at any time point. Investigating mechanisms of renal damage, protective SirT3 was decreased in CKD, which contrasted an increase in protein kinase B (AKT) expression, mechanistic target of rapamycin (mTOR) downstream signaling, induction of oxidative and endoplasmic reticulum (ER) stress. This occurred together with impaired renal mitochondrial function and accumulation of hexosylceramides (HexCer) as an established mediator of inflammation and mitochondrial dysfunction in the kidney. CONCLUSIONS 2,8-DHA-induced CKD results in renal activation of the mTOR downstream signaling, endoplasmic reticulum stress, tubular injury, fibrosis, inflammation, oxidative stress and impaired kidney mitochondrial function in conjunction with renal hexosylceramide accumulation in C57BL/6J mice.
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Affiliation(s)
- Julia Moellmann
- Department of Internal Medicine I, University Hospital Aachen, RWTH Aachen University, Aachen, Germany
| | - Katja Krueger
- Department of Internal Medicine I, University Hospital Aachen, RWTH Aachen University, Aachen, Germany
| | - Dickson W L Wong
- Institute of Pathology, University Hospital Aachen, RWTH Aachen University, Aachen, Germany
| | - Barbara M Klinkhammer
- Institute of Pathology, University Hospital Aachen, RWTH Aachen University, Aachen, Germany
| | - Eva M Buhl
- Institute of Pathology, University Hospital Aachen, RWTH Aachen University, Aachen, Germany; Department of Nephrology, RWTH Aachen University, Aachen, Germany; Electron Microscopy Facility, RWTH Aachen University, Aachen, Germany
| | - Jonas Dehairs
- Laboratory of Lipid Metabolism and Cancer, Department of Oncology, LKI - Leuven Cancer Institute, KU Leuven - University of Leuven, Leuven, Belgium
| | - Johan V Swinnen
- Laboratory of Lipid Metabolism and Cancer, Department of Oncology, LKI - Leuven Cancer Institute, KU Leuven - University of Leuven, Leuven, Belgium
| | - Heidi Noels
- Institute for Molecular Cardiovascular Research (IMCAR), RWTH Aachen University, Aachen, Germany
| | - Joachim Jankowski
- Institute for Molecular Cardiovascular Research (IMCAR), RWTH Aachen University, Aachen, Germany
| | - Corinna Lebherz
- Department of Internal Medicine I, University Hospital Aachen, RWTH Aachen University, Aachen, Germany
| | - Peter Boor
- Institute of Pathology, University Hospital Aachen, RWTH Aachen University, Aachen, Germany; Department of Nephrology, RWTH Aachen University, Aachen, Germany
| | - Nikolaus Marx
- Department of Internal Medicine I, University Hospital Aachen, RWTH Aachen University, Aachen, Germany
| | - Michael Lehrke
- Department of Internal Medicine I, University Hospital Aachen, RWTH Aachen University, Aachen, Germany.
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16
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Dupont N, Claude-Taupin A, Codogno P. A historical perspective of macroautophagy regulation by biochemical and biomechanical stimuli. FEBS Lett 2024; 598:17-31. [PMID: 37777819 DOI: 10.1002/1873-3468.14744] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2023] [Revised: 09/08/2023] [Accepted: 09/11/2023] [Indexed: 10/02/2023]
Abstract
Macroautophagy is a lysosomal degradative pathway for intracellular macromolecules, protein aggregates, and organelles. The formation of the autophagosome, a double membrane-bound structure that sequesters cargoes before their delivery to the lysosome, is regulated by several stimuli in multicellular organisms. Pioneering studies in rat liver showed the importance of amino acids, insulin, and glucagon in controlling macroautophagy. Thereafter, many studies have deciphered the signaling pathways downstream of these biochemical stimuli to control autophagosome formation. Two signaling hubs have emerged: the kinase mTOR, in a complex at the surface of lysosomes which is sensitive to nutrients and hormones; and AMPK, which is sensitive to the cellular energetic status. Besides nutritional, hormonal, and energetic fluctuations, many organs have to respond to mechanical forces (compression, stretching, and shear stress). Recent studies have shown the importance of mechanotransduction in controlling macroautophagy. This regulation engages cell surface sensors, such as the primary cilium, in order to translate mechanical stimuli into biological responses.
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Affiliation(s)
- Nicolas Dupont
- INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker-Enfants Malades, Université Paris Cité, France
| | - Aurore Claude-Taupin
- INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker-Enfants Malades, Université Paris Cité, France
| | - Patrice Codogno
- INSERM UMR-S1151, CNRS UMR-S8253, Institut Necker-Enfants Malades, Université Paris Cité, France
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17
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Bianco V, Kratky D. Glycoprotein Non-Metastatic Protein B (GPNMB): The Missing Link Between Lysosomes and Obesity. Exp Clin Endocrinol Diabetes 2023; 131:639-645. [PMID: 37956971 DOI: 10.1055/a-2192-0101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2023]
Abstract
As a result of an unhealthy diet and limited physical activity, obesity has become a widespread pandemic worldwide and is an important predictor for the development of cardiovascular disease. Obesity is often characterized by a pro-inflammatory environment in white adipose tissue (WAT), mainly due to increased macrophage infiltration. These immune cells boost their lipid concentrations by accumulating the content of dying adipocytes. As the lysosome is highly involved in lipid handling, the progressive lipid accumulation may result in lysosomal stress and a metabolic shift. Recent studies have identified glycoprotein non-metastatic melanoma protein B (GPNMB) as a novel marker of inflammatory diseases. GPNMB is a type I transmembrane protein on the cell surface of various cell types, such as macrophages, dendritic cells, osteoblasts, and microglia, from which it can be proteolytically cleaved into a soluble molecule. It is induced by lysosomal stress via microphthalmia-associated transcription factor and thus has been found to be upregulated in many lysosomal storage disorders. In addition, a clear connection between GPNMB and obesity was recently established. GPNMB was shown to have protective and anti-inflammatory effects in most cases, preventing the progression of obesity-related metabolic disorders. In contrast, soluble GPNMB likely has the opposite effect and promotes lipogenesis in WAT. This review aims to summarize and clarify the role of GPNMB in the progression of obesity and to highlight its potential use as a biomarker for lipid-associated disorders.
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Affiliation(s)
- Valentina Bianco
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
| | - Dagmar Kratky
- Gottfried Schatz Research Center, Molecular Biology and Biochemistry, Medical University of Graz, Graz, Austria
- BioTechMed-Graz, Graz, Austria
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18
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Maji S, Pirozzi M, Ruturaj, Pandey R, Ghosh T, Das S, Gupta A. Copper-independent lysosomal localisation of the Wilson disease protein ATP7B. Traffic 2023; 24:587-609. [PMID: 37846526 DOI: 10.1111/tra.12919] [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: 10/20/2022] [Revised: 09/10/2023] [Accepted: 09/23/2023] [Indexed: 10/18/2023]
Abstract
In hepatocytes, the Wilson disease protein ATP7B resides on the trans-Golgi network (TGN) and traffics to peripheral lysosomes to export excess intracellular copper through lysosomal exocytosis. We found that in basal copper or even upon copper chelation, a significant amount of ATP7B persists in the endolysosomal compartment of hepatocytes but not in non-hepatic cells. These ATP7B-harbouring lysosomes lie in close proximity of ~10 nm to the TGN. ATP7B constitutively distributes itself between the sub-domain of the TGN with a lower pH and the TGN-proximal lysosomal compartments. The presence of ATP7B on TGN-lysosome colocalising sites upon Golgi disruption suggested a possible exchange of ATP7B directly between the TGN and its proximal lysosomes. Manipulating lysosomal positioning significantly alters the localisation of ATP7B in the cell. Contrary to previous understanding, we found that upon copper chelation in a copper-replete hepatocyte, ATP7B is not retrieved back to TGN from peripheral lysosomes; rather, ATP7B recycles to these TGN-proximal lysosomes to initiate the next cycle of copper transport. We report a hitherto unknown copper-independent lysosomal localisation of ATP7B and the importance of TGN-proximal lysosomes but not TGN as the terminal acceptor organelle of ATP7B in its retrograde pathway.
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Affiliation(s)
- Saptarshi Maji
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | | | - Ruturaj
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Raviranjan Pandey
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Tamal Ghosh
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Santanu Das
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Arnab Gupta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
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19
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Li HP, Huang CY, Lui KW, Chao YK, Yeh CN, Lee LY, Huang Y, Lin TL, Kuo YC, Huang MY, Fan HC, Lin AC, Hsieh CH, Chang KP, Lin CY, Wang HM, Chao M, Liu JS, Chang YS, Hsu CL. Nasopharyngeal carcinoma patient-derived xenograft mouse models reveal potential drugs targeting cell cycle, mTOR, and autophagy pathways. Transl Oncol 2023; 38:101785. [PMID: 37713975 PMCID: PMC10509698 DOI: 10.1016/j.tranon.2023.101785] [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: 07/05/2023] [Revised: 09/05/2023] [Accepted: 09/08/2023] [Indexed: 09/17/2023] Open
Abstract
BACKGROUND Nasopharyngeal carcinoma (NPC) is associated with Epstein-Barr virus (EBV) infection. To test preclinical NPC drugs, we established two patient-derived xenograft (PDX) mouse models, EBV-positive PDX-B13 and EBV-negative PDX-Li41, for drug screening. METHODS Based on next generation sequencing (NGS) studies, PDX-B13 had CCND1 copy number (CN) gain but CDKN2A CN loss, whereas PDX-Li41 had CDKN2A and RB1 CN loss, TSC1 (negative regulator of mTOR) frameshift deletion mutation, and increased activation of mTOR, a serine/threonine kinase that governs metabolism, autophagy, and apoptosis. Increased mTOR was also associated with poor NPC prognosis. RESULTS Everolimus, an mTOR inhibitor, suppressed tumor growth in the two PDX NPC models and had an additive antitumor effect with palbociclib, a CDK4/6 inhibitor. PDX tumors treated with various drugs or untreated were subjected to RNA sequencing, transcriptome profile analysis, and selective Western blotting to understand the interactions between these drugs and gene expression profiles. Palbociclib also suppressed EB viral nuclear antigen (EBNA1) expression in PDX-B13. Everolimus together with autophagy inhibitor, hydroxychloroquine, had additive anti-tumor effect on PDX-B13 tumor. Immunohistochemistry revealed that high mTOR levels were correlated with poor overall survival in patients with metastatic NPC (N = 90). CONCLUSIONS High mTOR levels are a poor prognostic factor in NPC, and cell cycle, mTOR and autophagy pathways may serve as therapeutic targets in NPC. In addition, PDX models can be used for efficiently testing potential NPC drugs.
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Affiliation(s)
- Hsin-Pai Li
- Department of Microbiology and Immunology, Chang Gung University, Taoyuan 33305, Taiwan; Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan 33305, Taiwan; Molecular Medicine Research Center, Chang Gung University, Taoyuan 33305, Taiwan; Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Chen-Yang Huang
- Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Kar-Wai Lui
- Department of Medical Imaging and Intervention, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Yin-Kai Chao
- Division of Thoracic and Cardiovascular Surgery, Department of Surgery, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Chun-Nan Yeh
- Department of General Surgery, Liver Research Center, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Li-Yu Lee
- Department of Pathology, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Yenlin Huang
- Department of Pathology, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Tung-Liang Lin
- Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Yung-Chia Kuo
- Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Mei-Yuan Huang
- Department of Microbiology and Immunology, Chang Gung University, Taoyuan 33305, Taiwan
| | - Hsien-Chi Fan
- Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - An-Chi Lin
- Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Chia-Hsun Hsieh
- Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Kai-Ping Chang
- Department of Otolaryngology-Head and Neck Surgery, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Chien-Yu Lin
- Department of Radiation, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Hung-Ming Wang
- Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Mei Chao
- Department of Microbiology and Immunology, Chang Gung University, Taoyuan 33305, Taiwan; Graduate Institute of Biomedical Sciences, Chang Gung University, Taoyuan 33305, Taiwan; Department of Hepato-Gastroenterology, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Jai-Shin Liu
- Department of Biotechnology and Pharmaceutical Technology, Yuanpei University of Medical Technology, Hsinchu City 30015, Taiwan
| | - Yu-Sun Chang
- Department of Microbiology and Immunology, Chang Gung University, Taoyuan 33305, Taiwan; Molecular Medicine Research Center, Chang Gung University, Taoyuan 33305, Taiwan; Department of Otolaryngology-Head and Neck Surgery, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan
| | - Cheng-Lung Hsu
- Division of Hematology-Oncology, Department of Internal Medicine, Chang Gung Memorial Hospital, Chang Gung University, Taoyuan 33305, Taiwan; School of Medicine, Chang Gung University, Taoyuan 33305, Taiwan.
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20
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Wittenstein A, Caspi M, Rippin I, Elroy-Stein O, Eldar-Finkelman H, Thoms S, Rosin-Arbesfeld R. Nonsense mutation suppression is enhanced by targeting different stages of the protein synthesis process. PLoS Biol 2023; 21:e3002355. [PMID: 37943958 PMCID: PMC10684085 DOI: 10.1371/journal.pbio.3002355] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 11/28/2023] [Accepted: 09/29/2023] [Indexed: 11/12/2023] Open
Abstract
The introduction of premature termination codons (PTCs), as a result of splicing defects, insertions, deletions, or point mutations (also termed nonsense mutations), lead to numerous genetic diseases, ranging from rare neuro-metabolic disorders to relatively common inheritable cancer syndromes and muscular dystrophies. Over the years, a large number of studies have demonstrated that certain antibiotics and other synthetic molecules can act as PTC suppressors by inducing readthrough of nonsense mutations, thereby restoring the expression of full-length proteins. Unfortunately, most PTC readthrough-inducing agents are toxic, have limited effects, and cannot be used for therapeutic purposes. Thus, further efforts are required to improve the clinical outcome of nonsense mutation suppressors. Here, by focusing on enhancing readthrough of pathogenic nonsense mutations in the adenomatous polyposis coli (APC) tumor suppressor gene, we show that disturbing the protein translation initiation complex, as well as targeting other stages of the protein translation machinery, enhances both antibiotic and non-antibiotic-mediated readthrough of nonsense mutations. These findings strongly increase our understanding of the mechanisms involved in nonsense mutation readthrough and facilitate the development of novel therapeutic targets for nonsense suppression to restore protein expression from a large variety of disease-causing mutated transcripts.
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Affiliation(s)
- Amnon Wittenstein
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Michal Caspi
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ido Rippin
- The Department of Human Molecular Genetics & Biochemistry School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Orna Elroy-Stein
- Shmunis School of Biomedicine and Cancer Research, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, Israel
| | - Hagit Eldar-Finkelman
- The Department of Human Molecular Genetics & Biochemistry School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Sven Thoms
- Biochemistry and Molecular Medicine, Medical School EWL, Bielefeld University, Bielefeld, Germany
| | - Rina Rosin-Arbesfeld
- Department of Clinical Microbiology and Immunology, Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
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21
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Lyons AC, Mehta S, Zhang J. Fluorescent biosensors illuminate the spatial regulation of cell signaling across scales. Biochem J 2023; 480:1693-1717. [PMID: 37903110 PMCID: PMC10657186 DOI: 10.1042/bcj20220223] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 10/11/2023] [Accepted: 10/13/2023] [Indexed: 11/01/2023]
Abstract
As cell signaling research has advanced, it has become clearer that signal transduction has complex spatiotemporal regulation that goes beyond foundational linear transduction models. Several technologies have enabled these discoveries, including fluorescent biosensors designed to report live biochemical signaling events. As genetically encoded and live-cell compatible tools, fluorescent biosensors are well suited to address diverse cell signaling questions across different spatial scales of regulation. In this review, methods of examining spatial signaling regulation and the design of fluorescent biosensors are introduced. Then, recent biosensor developments that illuminate the importance of spatial regulation in cell signaling are highlighted at several scales, including membranes and organelles, molecular assemblies, and cell/tissue heterogeneity. In closing, perspectives on how fluorescent biosensors will continue enhancing cell signaling research are discussed.
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Affiliation(s)
- Anne C. Lyons
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, U.S.A
- Shu Chien-Gene Lay Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, U.S.A
| | - Sohum Mehta
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, U.S.A
| | - Jin Zhang
- Department of Pharmacology, University of California, San Diego, La Jolla, CA 92093, U.S.A
- Shu Chien-Gene Lay Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, U.S.A
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, U.S.A
- Moores Cancer Center, University of California, San Diego, La Jolla, CA 92093, U.S.A
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22
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Geng S, Lu R, Zhang Y, Wu Y, Xie L, Caldwell B, Pradhan K, Yi Z, Hou J, Xu F, Chen X, Li L. Monocytes reprogrammed by 4-PBA potently contribute to the resolution of inflammation and atherosclerosis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.19.563200. [PMID: 37961551 PMCID: PMC10634693 DOI: 10.1101/2023.10.19.563200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Background Chronic inflammation initiated by inflammatory monocytes underlies the pathogenesis of atherosclerosis. However, approaches that can effectively resolve chronic low-grade inflammation targeting monocytes are not readily available. The small chemical compound 4-phenylbutyric acid (4-PBA) exhibits broad anti-inflammatory effects in reducing atherosclerosis. Selective delivery of 4-PBA reprogrammed monocytes may hold novel potential in providing targeted and precision therapeutics for the treatment of atherosclerosis. Methods Systems analyses integrating single-cell RNA-sequencing and complementary immunological approaches characterized key resolving characteristics as well as defining markers of reprogrammed monocytes trained by 4-PBA. Molecular mechanisms responsible for monocyte reprogramming was assessed by integrated biochemical and genetic approaches. The inter-cellular propagation of homeostasis resolution was evaluated by co-culture assays with donor monocytes trained by 4-PBA and recipient naïve monocytes. The in vivo effects of monocyte resolution and atherosclerosis prevention by 4-PBA were assessed with the high fat diet-fed ApoE -/- mouse model with i.p. 4-PBA administration. Furthermore, the selective efficacy of 4-PBA trained monocytes were examined by i.v. transfusion of ex vivo trained monocytes by 4-PBA into recipient high fat diet-fed ApoE -/- mice. Results In this study, we found that monocytes can be potently reprogrammed by 4-PBA into an immune-resolving state characterized by reduced adhesion and enhanced expression of anti-inflammatory mediator CD24. Mechanistically, 4-PBA reduced the expression of ICAM-1 via reducing peroxisome stress and attenuating SYK-mTOR signaling. Concurrently, 4-PBA enhanced the expression of resolving mediator CD24 through promoting PPARγ neddylation mediated by TOLLIP. 4-PBA trained monocytes can effectively propagate anti-inflammation activity to neighboring monocytes through CD24. Our data further demonstrated that 4-PBA trained monocytes effectively reduce atherosclerosis pathogenesis when administered in vivo . Conclusion Our study describes a robust and effective approach to generate resolving monocytes, characterizes novel mechanisms for targeted monocyte reprogramming, and offers a precision-therapeutics for atherosclerosis based on delivering reprogrammed resolving monocytes.
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23
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Su H, Guo H, Qiu X, Lin TY, Qin C, Celio G, Yong P, Senders M, Han X, Bernlohr DA, Chen X. Lipocalin 2 regulates mitochondrial phospholipidome remodeling, dynamics, and function in brown adipose tissue in male mice. Nat Commun 2023; 14:6729. [PMID: 37872178 PMCID: PMC10593768 DOI: 10.1038/s41467-023-42473-2] [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: 11/17/2022] [Accepted: 10/11/2023] [Indexed: 10/25/2023] Open
Abstract
Mitochondrial function is vital for energy metabolism in thermogenic adipocytes. Impaired mitochondrial bioenergetics in brown adipocytes are linked to disrupted thermogenesis and energy balance in obesity and aging. Phospholipid cardiolipin (CL) and phosphatidic acid (PA) jointly regulate mitochondrial membrane architecture and dynamics, with mitochondria-associated endoplasmic reticulum membranes (MAMs) serving as the platform for phospholipid biosynthesis and metabolism. However, little is known about the regulators of MAM phospholipid metabolism and their connection to mitochondrial function. We discover that LCN2 is a PA binding protein recruited to the MAM during inflammation and metabolic stimulation. Lcn2 deficiency disrupts mitochondrial fusion-fission balance and alters the acyl-chain composition of mitochondrial phospholipids in brown adipose tissue (BAT) of male mice. Lcn2 KO male mice exhibit an increase in the levels of CLs containing long-chain polyunsaturated fatty acids (LC-PUFA), a decrease in CLs containing monounsaturated fatty acids, resulting in mitochondrial dysfunction. This dysfunction triggers compensatory activation of peroxisomal function and the biosynthesis of LC-PUFA-containing plasmalogens in BAT. Additionally, Lcn2 deficiency alters PA production, correlating with changes in PA-regulated phospholipid-metabolizing enzymes and the mTOR signaling pathway. In conclusion, LCN2 plays a critical role in the acyl-chain remodeling of phospholipids and mitochondrial bioenergetics by regulating PA production and its function in activating signaling pathways.
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Affiliation(s)
- Hongming Su
- Department of Food Science and Nutrition, University of Minnesota-Twin Cities, St. Paul, MN, 55108, USA
| | - Hong Guo
- Department of Food Science and Nutrition, University of Minnesota-Twin Cities, St. Paul, MN, 55108, USA
| | - Xiaoxue Qiu
- Department of Food Science and Nutrition, University of Minnesota-Twin Cities, St. Paul, MN, 55108, USA
| | - Te-Yueh Lin
- Department of Food Science and Nutrition, University of Minnesota-Twin Cities, St. Paul, MN, 55108, USA
| | - Chao Qin
- Barshop Institute for Longevity and Aging Studies, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229-3900, USA
| | - Gail Celio
- University Imaging Centers, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - Peter Yong
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - Mark Senders
- University Imaging Centers, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - Xianlin Han
- Barshop Institute for Longevity and Aging Studies, Department of Medicine, University of Texas Health Science Center at San Antonio, San Antonio, TX, 78229-3900, USA
| | - David A Bernlohr
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota-Twin Cities, Minneapolis, MN, 55455, USA
| | - Xiaoli Chen
- Department of Food Science and Nutrition, University of Minnesota-Twin Cities, St. Paul, MN, 55108, USA.
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24
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He L, Chen J, Deng P, Huang S, Liu P, Wang C, Huang X, Li Y, Chen B, Shi D, Xiao Y, Chen X, Ouyang Y, Song L, Lin C. Lysosomal cyst(e)ine storage potentiates tolerance to oxidative stress in cancer cells. Mol Cell 2023; 83:3502-3519.e11. [PMID: 37751742 DOI: 10.1016/j.molcel.2023.08.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Revised: 07/17/2023] [Accepted: 08/30/2023] [Indexed: 09/28/2023]
Abstract
Cyst(e)ine is a key precursor for the synthesis of glutathione (GSH), which protects cancer cells from oxidative stress. Cyst(e)ine is stored in lysosomes, but its role in redox regulation is unclear. Here, we show that breast cancer cells upregulate major facilitator superfamily domain containing 12 (MFSD12) to increase lysosomal cyst(e)ine storage, which is released by cystinosin (CTNS) to maintain GSH levels and buffer oxidative stress. We find that mTORC1 regulates MFSD12 by directly phosphorylating residue T254, while mTORC1 inhibition enhances lysosome acidification that activates CTNS. This switch modulates lysosomal cyst(e)ine levels in response to oxidative stress, fine-tuning redox homeostasis to enhance cell fitness. MFSD12-T254A mutant inhibits MFSD12 function and suppresses tumor progression. Moreover, MFSD12 overexpression correlates with poor neoadjuvant chemotherapy response and prognosis in breast cancer patients. Our findings reveal the critical role of lysosomal cyst(e)ine storage in adaptive redox homeostasis and suggest that MFSD12 is a potential therapeutic target.
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Affiliation(s)
- Lixin He
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Jinxin Chen
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Pinwei Deng
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Shumei Huang
- Department of Biochemistry, Zhongshan School of Medicine, Sun Yat-sen University, Guangzhou 510080, China
| | - Pian Liu
- Cancer Center, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China
| | - Chanjuan Wang
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Xinjian Huang
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Yue Li
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Boyu Chen
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Dongni Shi
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Yunyun Xiao
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Xiangfu Chen
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Ying Ouyang
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China
| | - Libing Song
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Key Laboratory of Protein Modification and Degradation, School of Basic Medical Sciences, Guangzhou Institute of Oncology, Tumor Hospital, Guangzhou Medical University, Guangzhou 510080, China
| | - Chuyong Lin
- Department of Experimental Research, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Sun Yat-sen University Cancer Center, Guangzhou 510060, China; Guangdong Esophageal Cancer Institute, Guangzhou 510060, China.
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25
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Reichlmeir M, Canet-Pons J, Koepf G, Nurieva W, Duecker RP, Doering C, Abell K, Key J, Stokes MP, Zielen S, Schubert R, Ivics Z, Auburger G. In Cerebellar Atrophy of 12-Month-Old ATM-Null Mice, Transcriptome Upregulations Concern Most Neurotransmission and Neuropeptide Pathways, While Downregulations Affect Prominently Itpr1, Usp2 and Non-Coding RNA. Cells 2023; 12:2399. [PMID: 37830614 PMCID: PMC10572167 DOI: 10.3390/cells12192399] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 09/29/2023] [Accepted: 10/01/2023] [Indexed: 10/14/2023] Open
Abstract
The autosomal recessive disorder Ataxia-Telangiectasia is caused by a dysfunction of the stress response protein, ATM. In the nucleus of proliferating cells, ATM senses DNA double-strand breaks and coordinates their repair. This role explains T-cell dysfunction and tumour risk. However, it remains unclear whether this function is relevant for postmitotic neurons and underlies cerebellar atrophy, since ATM is cytoplasmic in postmitotic neurons. Here, we used ATM-null mice that survived early immune deficits via bone-marrow transplantation, and that reached initial neurodegeneration stages at 12 months of age. Global cerebellar transcriptomics demonstrated that ATM depletion triggered upregulations in most neurotransmission and neuropeptide systems. Downregulated transcripts were found for the ATM interactome component Usp2, many non-coding RNAs, ataxia genes Itpr1, Grid2, immediate early genes and immunity factors. Allelic splice changes affected prominently the neuropeptide machinery, e.g., Oprm1. Validation experiments with stressors were performed in human neuroblastoma cells, where ATM was localised only to cytoplasm, similar to the brain. Effect confirmation in SH-SY5Y cells occurred after ATM depletion and osmotic stress better than nutrient/oxidative stress, but not after ATM kinase inhibition or DNA stressor bleomycin. Overall, we provide pioneer observations from a faithful A-T mouse model, which suggest general changes in synaptic and dense-core vesicle stress adaptation.
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Affiliation(s)
- Marina Reichlmeir
- Goethe University Frankfurt, University Hospital, Clinic of Neurology, Exp. Neurology, Heinrich Hoffmann Str. 7, 60590 Frankfurt am Main, Germany; (M.R.); (J.C.-P.); (J.K.)
| | - Júlia Canet-Pons
- Goethe University Frankfurt, University Hospital, Clinic of Neurology, Exp. Neurology, Heinrich Hoffmann Str. 7, 60590 Frankfurt am Main, Germany; (M.R.); (J.C.-P.); (J.K.)
| | - Gabriele Koepf
- Goethe University Frankfurt, University Hospital, Clinic of Neurology, Exp. Neurology, Heinrich Hoffmann Str. 7, 60590 Frankfurt am Main, Germany; (M.R.); (J.C.-P.); (J.K.)
| | - Wasifa Nurieva
- Transposition and Genome Engineering, Research Centre of the Division of Hematology, Gene and Cell Therapy, Paul Ehrlich Institute, 63225 Langen, Germany; (W.N.); (Z.I.)
| | - Ruth Pia Duecker
- Division of Pediatrics, Pulmonology, Allergology, Infectious Diseases and Gastroenterology, Children’s Hospital, University Hospital, Goethe-University, 60590 Frankfurt am Main, Germany; (R.P.D.); (S.Z.); (R.S.)
| | - Claudia Doering
- Dr. Senckenberg Institute of Pathology, University Hospital Frankfurt, 60590 Frankfurt am Main, Germany;
| | - Kathryn Abell
- Cell Signaling Technology, Inc., Danvers, MA 01923, USA; (K.A.); (M.P.S.)
| | - Jana Key
- Goethe University Frankfurt, University Hospital, Clinic of Neurology, Exp. Neurology, Heinrich Hoffmann Str. 7, 60590 Frankfurt am Main, Germany; (M.R.); (J.C.-P.); (J.K.)
| | - Matthew P. Stokes
- Cell Signaling Technology, Inc., Danvers, MA 01923, USA; (K.A.); (M.P.S.)
| | - Stefan Zielen
- Division of Pediatrics, Pulmonology, Allergology, Infectious Diseases and Gastroenterology, Children’s Hospital, University Hospital, Goethe-University, 60590 Frankfurt am Main, Germany; (R.P.D.); (S.Z.); (R.S.)
- Respiratory Research Institute, Medaimun GmbH, 60596 Frankfurt am Main, Germany
| | - Ralf Schubert
- Division of Pediatrics, Pulmonology, Allergology, Infectious Diseases and Gastroenterology, Children’s Hospital, University Hospital, Goethe-University, 60590 Frankfurt am Main, Germany; (R.P.D.); (S.Z.); (R.S.)
| | - Zoltán Ivics
- Transposition and Genome Engineering, Research Centre of the Division of Hematology, Gene and Cell Therapy, Paul Ehrlich Institute, 63225 Langen, Germany; (W.N.); (Z.I.)
| | - Georg Auburger
- Goethe University Frankfurt, University Hospital, Clinic of Neurology, Exp. Neurology, Heinrich Hoffmann Str. 7, 60590 Frankfurt am Main, Germany; (M.R.); (J.C.-P.); (J.K.)
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26
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Casagrande S, Loveland JL, Oefele M, Boner W, Lupi S, Stier A, Hau M. Dietary nucleotides can prevent glucocorticoid-induced telomere attrition in a fast-growing wild vertebrate. Mol Ecol 2023; 32:5429-5447. [PMID: 37658759 DOI: 10.1111/mec.17114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 07/20/2023] [Accepted: 08/09/2023] [Indexed: 09/05/2023]
Abstract
Telomeres are chromosome protectors that shorten during eukaryotic cell replication and in stressful conditions. Developing individuals are susceptible to telomere erosion when their growth is fast and resources are limited. This is critical because the rate of telomere attrition in early life is linked to health and life span of adults. The metabolic telomere attrition hypothesis (MeTA) suggests that telomere dynamics can respond to biochemical signals conveying information about the organism's energetic state. Among these signals are glucocorticoids, hormones that promote catabolic processes, potentially impairing costly telomere maintenance, and nucleotides, which activate anabolic pathways through the cellular enzyme target of rapamycin (TOR), thus preventing telomere attrition. During the energetically demanding growth phase, the regulation of telomeres in response to two contrasting signals - one promoting telomere maintenance and the other attrition - provides an ideal experimental setting to test the MeTA. We studied nestlings of a rapidly developing free-living passerine, the great tit (Parus major), that either received glucocorticoids (Cort-chicks), nucleotides (Nuc-chicks) or a combination of both (NucCort-chicks), comparing these with controls (Cnt-chicks). As expected, Cort-chicks showed telomere attrition, while NucCort- and Nuc-chicks did not. NucCort-chicks was the only group showing increased expression of a proxy for TOR activation (the gene TELO2), of mitochondrial enzymes linked to ATP production (cytochrome oxidase and ATP-synthase) and a higher efficiency in aerobically producing ATP. NucCort-chicks had also a higher expression of telomere maintenance genes (shelterin protein TERF2 and telomerase TERT) and of enzymatic antioxidant genes (glutathione peroxidase and superoxide dismutase). The findings show that nucleotide availability is crucial for preventing telomere erosion during fast growth in stressful environments.
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Affiliation(s)
- Stefania Casagrande
- Max Planck Institute for Biological Intelligence, Evolutionary Physiology Group, Seewiesen, Germany
| | - Jasmine L Loveland
- Department of Cognitive and Behavioral Biology, University of Vienna, Vienna, Austria
| | - Marlene Oefele
- Max Planck Institute for Biological Intelligence, Evolutionary Physiology Group, Seewiesen, Germany
| | - Winnie Boner
- Institute of Biodiversity Animal Health and Comparative Medicine, University of Glasgow, Glasgow, UK
| | - Sara Lupi
- Konrad Lorenz Institute of Ethology, Vienna, Austria
| | - Antoine Stier
- Université de Strasbourg, CNRS, Institut Pluridisciplinaire Hubert Curien, UMR7178, Strasbourg, France
- Department of Biology, University of Turku, Turku, Finland
| | - Michaela Hau
- Max Planck Institute for Biological Intelligence, Evolutionary Physiology Group, Seewiesen, Germany
- Department of Biology, University of Konstanz, Constance, Germany
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27
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Voss PA, Gornik SG, Jacobovitz MR, Rupp S, Dörr M, Maegele I, Guse A. Host nutrient sensing is mediated by mTOR signaling in cnidarian-dinoflagellate symbiosis. Curr Biol 2023; 33:3634-3647.e5. [PMID: 37572664 DOI: 10.1016/j.cub.2023.07.038] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 05/31/2023] [Accepted: 07/20/2023] [Indexed: 08/14/2023]
Abstract
To survive in the nutrient-poor waters of the tropics, reef-building corals rely on intracellular, photosynthetic dinoflagellate symbionts. Photosynthates produced by the symbiont are translocated to the host, and this enables corals to form the structural foundation of the most biodiverse of all marine ecosystems. Although the regulation of nutrient exchange between partners is critical for ecosystem stability and health, the mechanisms governing how nutrients are sensed, transferred, and integrated into host cell processes are largely unknown. Ubiquitous among eukaryotes, the mechanistic target of the rapamycin (mTOR) signaling pathway integrates intracellular and extracellular stimuli to influence cell growth and cell-cycle progression and to balance metabolic processes. A functional role of mTOR in the integration of host and symbiont was demonstrated in various nutritional symbioses, and a similar role of mTOR was proposed for coral-algal symbioses. Using the endosymbiosis model Aiptasia, we examined the role of mTOR signaling in both larvae and adult polyps across various stages of symbiosis. We found that symbiosis enhances cell proliferation, and using an Aiptasia-specific antibody, we localized mTOR to symbiosome membranes. We found that mTOR signaling is activated by symbiosis, while inhibition of mTOR signaling disrupts intracellular niche establishment and symbiosis altogether. Additionally, we observed that dysbiosis was a conserved response to mTOR inhibition in the larvae of a reef-building coral species. Our data confim that mTOR signaling plays a pivotal role in integrating symbiont-derived nutrients into host metabolism and symbiosis stability, ultimately allowing symbiotic cnidarians to thrive in challenging environments.
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Affiliation(s)
- Philipp A Voss
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, Heidelberg 69120 Germany
| | - Sebastian G Gornik
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, Heidelberg 69120 Germany
| | - Marie R Jacobovitz
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, Heidelberg 69120 Germany
| | - Sebastian Rupp
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, Heidelberg 69120 Germany
| | - Melanie Dörr
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, Heidelberg 69120 Germany
| | - Ira Maegele
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, Heidelberg 69120 Germany
| | - Annika Guse
- Centre for Organismal Studies, Heidelberg University, Im Neuenheimer Feld 230, Heidelberg 69120 Germany.
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28
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Kaspy MS, Hannaian SJ, Bell ZW, Churchward-Venne TA. The effects of branched-chain amino acids on muscle protein synthesis, muscle protein breakdown and associated molecular signalling responses in humans: an update. Nutr Res Rev 2023:1-14. [PMID: 37681443 DOI: 10.1017/s0954422423000197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/09/2023]
Abstract
Branched-chain amino acids (BCAA: leucine, isoleucine and valine) are three of the nine indispensable amino acids, and are frequently consumed as a dietary supplement by athletes and recreationally active individuals alike. The popularity of BCAA supplements is largely predicated on the notion that they can stimulate rates of muscle protein synthesis (MPS) and suppress rates of muscle protein breakdown (MPB), the combination of which promotes a net anabolic response in skeletal muscle. To date, several studies have shown that BCAA (particularly leucine) increase the phosphorylation status of key proteins within the mechanistic target of rapamycin (mTOR) signalling pathway involved in the regulation of translation initiation in human muscle. Early research in humans demonstrated that BCAA provision reduced indices of whole-body protein breakdown and MPB; however, there was no stimulatory effect of BCAA on MPS. In contrast, recent work has demonstrated that BCAA intake can stimulate postprandial MPS rates at rest and can further increase MPS rates during recovery after a bout of resistance exercise. The purpose of this evidence-based narrative review is to critically appraise the available research pertaining to studies examining the effects of BCAA on MPS, MPB and associated molecular signalling responses in humans. Overall, BCAA can activate molecular pathways that regulate translation initiation, reduce indices of whole-body and MPB, and transiently stimulate MPS rates. However, the stimulatory effect of BCAA on MPS rates is less than the response observed following ingestion of a complete protein source providing the full complement of indispensable amino acids.
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Affiliation(s)
- Matthew S Kaspy
- Department of Kinesiology and Physical Education, McGill University, 475 Avenue Des Pins H2W 1S4, Montreal, QC, Canada
| | - Sarkis J Hannaian
- Department of Kinesiology and Physical Education, McGill University, 475 Avenue Des Pins H2W 1S4, Montreal, QC, Canada
- Research Institute of the McGill University Health Centre, Glen Site, 1001 Boul. Décarie, H4A 3J1 Montreal, QC, Canada
| | - Zachary W Bell
- Department of Kinesiology and Physical Education, McGill University, 475 Avenue Des Pins H2W 1S4, Montreal, QC, Canada
| | - Tyler A Churchward-Venne
- Department of Kinesiology and Physical Education, McGill University, 475 Avenue Des Pins H2W 1S4, Montreal, QC, Canada
- Division of Geriatric Medicine, McGill University, Montreal General Hospital, Room D6 237.F, 1650 Cedar Avenue, H3G 1A4, Montreal, QC, Canada
- Research Institute of the McGill University Health Centre, Glen Site, 1001 Boul. Décarie, H4A 3J1 Montreal, QC, Canada
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29
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de Wet S, Theart R, Loos B. Cogs in the autophagic machine-equipped to combat dementia-prone neurodegenerative diseases. Front Mol Neurosci 2023; 16:1225227. [PMID: 37720551 PMCID: PMC10500130 DOI: 10.3389/fnmol.2023.1225227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 07/31/2023] [Indexed: 09/19/2023] Open
Abstract
Neurodegenerative diseases are often characterized by hydrophobic inclusion bodies, and it may be the case that the aggregate-prone proteins that comprise these inclusion bodies are in fact the cause of neurotoxicity. Indeed, the appearance of protein aggregates leads to a proteostatic imbalance that causes various interruptions in physiological cellular processes, including lysosomal and mitochondrial dysfunction, as well as break down in calcium homeostasis. Oftentimes the approach to counteract proteotoxicity is taken to merely upregulate autophagy, measured by an increase in autophagosomes, without a deeper assessment of contributors toward effective turnover through autophagy. There are various ways in which autophagy is regulated ranging from the mammalian target of rapamycin (mTOR) to acetylation status of proteins. Healthy mitochondria and the intracellular energetic charge they preserve are key for the acidification status of lysosomes and thus ensuring effective clearance of components through the autophagy pathway. Both mitochondria and lysosomes have been shown to bear functional protein complexes that aid in the regulation of autophagy. Indeed, it may be the case that minimizing the proteins associated with the respective neurodegenerative pathology may be of greater importance than addressing molecularly their resulting inclusion bodies. It is in this context that this review will dissect the autophagy signaling pathway, its control and the manner in which it is molecularly and functionally connected with the mitochondrial and lysosomal system, as well as provide a summary of the role of autophagy dysfunction in driving neurodegenerative disease as a means to better position the potential of rapamycin-mediated bioactivities to control autophagy favorably.
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Affiliation(s)
- Sholto de Wet
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
| | - Rensu Theart
- Department of Electric and Electronic Engineering, Stellenbosch University, Stellenbosch, South Africa
| | - Ben Loos
- Department of Physiological Sciences, Stellenbosch University, Stellenbosch, South Africa
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30
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Gao Y, Tian T. mTOR Signaling Pathway and Gut Microbiota in Various Disorders: Mechanisms and Potential Drugs in Pharmacotherapy. Int J Mol Sci 2023; 24:11811. [PMID: 37511569 PMCID: PMC10380532 DOI: 10.3390/ijms241411811] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Revised: 07/15/2023] [Accepted: 07/18/2023] [Indexed: 07/30/2023] Open
Abstract
The mammalian or mechanistic target of rapamycin (mTOR) integrates multiple intracellular and extracellular upstream signals involved in the regulation of anabolic and catabolic processes in cells and plays a key regulatory role in cell growth and metabolism. The activation of the mTOR signaling pathway has been reported to be associated with a wide range of human diseases. A growing number of in vivo and in vitro studies have demonstrated that gut microbes and their complex metabolites can regulate host metabolic and immune responses through the mTOR pathway and result in disorders of host physiological functions. In this review, we summarize the regulatory mechanisms of gut microbes and mTOR in different diseases and discuss the crosstalk between gut microbes and their metabolites and mTOR in disorders in the gastrointestinal tract, liver, heart, and other organs. We also discuss the promising application of multiple potential drugs that can adjust the gut microbiota and mTOR signaling pathways. Despite the limited findings between gut microbes and mTOR, elucidating their relationship may provide new clues for the prevention and treatment of various diseases.
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Affiliation(s)
- Yuan Gao
- College of Life Science and Bioengineering, Beijing Jiaotong University, Beijing 100044, China
| | - Tian Tian
- College of Life Science and Bioengineering, Beijing Jiaotong University, Beijing 100044, China
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Jeong MH, Urquhart G, Lewis C, Chi Z, Jewell JL. Inhibition of phosphodiesterase 4D suppresses mTORC1 signaling and pancreatic cancer growth. JCI Insight 2023; 8:e158098. [PMID: 37427586 PMCID: PMC10371348 DOI: 10.1172/jci.insight.158098] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 05/23/2023] [Indexed: 07/11/2023] Open
Abstract
The mammalian target of rapamycin complex 1 (mTORC1) senses multiple upstream stimuli to orchestrate anabolic and catabolic events that regulate cell growth and metabolism. Hyperactivation of mTORC1 signaling is observed in multiple human diseases; thus, pathways that suppress mTORC1 signaling may help to identify new therapeutic targets. Here, we report that phosphodiesterase 4D (PDE4D) promotes pancreatic cancer tumor growth by increasing mTORC1 signaling. GPCRs paired to Gαs proteins activate adenylyl cyclase, which in turn elevates levels of 3',5'-cyclic adenosine monophosphate (cAMP), whereas PDEs catalyze the hydrolysis of cAMP to 5'-AMP. PDE4D forms a complex with mTORC1 and is required for mTORC1 lysosomal localization and activation. Inhibition of PDE4D and the elevation of cAMP levels block mTORC1 signaling via Raptor phosphorylation. Moreover, pancreatic cancer exhibits an upregulation of PDE4D expression, and high PDE4D levels predict the poor overall survival of patients with pancreatic cancer. Importantly, FDA-approved PDE4 inhibitors repress pancreatic cancer cell tumor growth in vivo by suppressing mTORC1 signaling. Our results identify PDE4D as an important activator of mTORC1 and suggest that targeting PDE4 with FDA-approved inhibitors may be beneficial for the treatment of human diseases with hyperactivated mTORC1 signaling.
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Affiliation(s)
- Mi-Hyeon Jeong
- Department of Molecular Biology
- Harold C. Simmons Comprehensive Cancer Center
- Hamon Center for Regenerative Science and Medicine, and
| | - Greg Urquhart
- Department of Molecular Biology
- Harold C. Simmons Comprehensive Cancer Center
- Hamon Center for Regenerative Science and Medicine, and
| | | | - Zhikai Chi
- Department of Pathology, University of Texas Southwestern Medical Center, Dallas, Texas, USA
| | - Jenna L. Jewell
- Department of Molecular Biology
- Harold C. Simmons Comprehensive Cancer Center
- Hamon Center for Regenerative Science and Medicine, and
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32
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Dunlap KR, Steiner JL, Hickner RC, Chase PB, Gordon BS. The duration of glucocorticoid treatment alters the anabolic response to high-force muscle contractions. J Appl Physiol (1985) 2023; 135:183-195. [PMID: 37289956 PMCID: PMC10312323 DOI: 10.1152/japplphysiol.00113.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 05/11/2023] [Accepted: 05/29/2023] [Indexed: 06/10/2023] Open
Abstract
Glucocorticoids induce a myopathy that includes loss of muscle mass and strength. Resistance exercise may reverse the muscle loss because it induces an anabolic response characterized by increases in muscle protein synthesis and potentially suppressing protein breakdown. Whether resistance exercise induces an anabolic response in glucocorticoid myopathic muscle is unknown, which is a problem because long-term glucocorticoid exposure alters the expression of genes that may prevent an anabolic response by limiting activation of pathways such as the mechanistic target of rapamycin in complex 1 (mTORC1). The purpose of this study was to assess whether high-force contractions initiate an anabolic response in glucocorticoid myopathic muscle. The anabolic response was analyzed by treating female mice with dexamethasone (DEX) for 7 days or 15 days. After treatment, the left tibialis anterior muscle of all mice was contracted via electrical stimulation of the sciatic nerve. Muscles were harvested 4 h after contractions. Rates of muscle protein synthesis were estimated using the SUnSET method. After 7 days of treatment, high-force contractions increased protein synthesis and mTORC1 signaling in both groups. After 15 days of treatment, high-force contractions activated mTORC1 signaling equally in both groups, but protein synthesis was only increased in control mice. The failure to increase protein synthesis may be because baseline synthetic rates were elevated in DEX-treated mice. The LC3 II/I ratio marker of autophagy was decreased by contractions regardless of treatment duration. These data show duration of glucocorticoid treatment alters the anabolic response to high-force contractions.NEW & NOTEWORTHY Glucocorticoid myopathy is the most common, toxic, noninflammatory myopathy. Our work shows that high-force contractions increase protein synthesis in skeletal muscle following short-term glucocorticoid treatment. However, longer duration glucocorticoid treatment results in anabolic resistance to high-force contractions despite activation of the mechanistic target of rapamycin in complex 1 (mTORC1) signaling pathway. This work defines potential limits for high-force contractions to activate the processes that would restore lost muscle mass in glucocorticoid myopathic patients.
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Affiliation(s)
- Kirsten R Dunlap
- Department of Nutrition and Integrative Physiology, Florida State University, Tallahassee, Florida, United States
| | - Jennifer L Steiner
- Department of Nutrition and Integrative Physiology, Florida State University, Tallahassee, Florida, United States
- Institute of Sports Sciences and Medicine, Florida State University, Tallahassee, Florida, United States
| | - Robert C Hickner
- Department of Nutrition and Integrative Physiology, Florida State University, Tallahassee, Florida, United States
- Institute of Sports Sciences and Medicine, Florida State University, Tallahassee, Florida, United States
| | - P Bryant Chase
- Department of Biological Science, Florida State University, Tallahassee, Florida, United States
| | - Bradley S Gordon
- Department of Nutrition and Integrative Physiology, Florida State University, Tallahassee, Florida, United States
- Institute of Sports Sciences and Medicine, Florida State University, Tallahassee, Florida, United States
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33
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Bassal MA. The Interplay between Dysregulated Metabolism and Epigenetics in Cancer. Biomolecules 2023; 13:944. [PMID: 37371524 DOI: 10.3390/biom13060944] [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: 04/24/2023] [Revised: 05/21/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
Cellular metabolism (or energetics) and epigenetics are tightly coupled cellular processes. It is arguable that of all the described cancer hallmarks, dysregulated cellular energetics and epigenetics are the most tightly coregulated. Cellular metabolic states regulate and drive epigenetic changes while also being capable of influencing, if not driving, epigenetic reprogramming. Conversely, epigenetic changes can drive altered and compensatory metabolic states. Cancer cells meticulously modify and control each of these two linked cellular processes in order to maintain their tumorigenic potential and capacity. This review aims to explore the interplay between these two processes and discuss how each affects the other, driving and enhancing tumorigenic states in certain contexts.
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Affiliation(s)
- Mahmoud Adel Bassal
- Cancer Science Institute of Singapore, National University of Singapore, Singapore 117599, Singapore
- Harvard Stem Cell Institute, Harvard Medical School, Boston, MA 02115, USA
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34
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Sharp ZD, Strong R. Rapamycin, the only drug that has been consistently demonstrated to increase mammalian longevity. An update. Exp Gerontol 2023; 176:112166. [PMID: 37011714 PMCID: PMC10868408 DOI: 10.1016/j.exger.2023.112166] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/30/2023] [Accepted: 03/31/2023] [Indexed: 04/05/2023]
Affiliation(s)
- Zelton Dave Sharp
- Department of Molecular Medicine and Institute of Biotechnology, San Antonio, TX, United States of America; Barshop Institute for Longevity and Aging Studies, San Antonio, TX, United States of America; Mays Cancer Center, San Antonio, TX, United States of America.
| | - Randy Strong
- Barshop Institute for Longevity and Aging Studies, San Antonio, TX, United States of America; Department of Pharmacology, UT Health, San Antonio, TX, United States of America; Research Service of the South Texas Veterans Health Care System, San Antonio, TX 78229, United States of America.
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Badoiu SC, Greabu M, Miricescu D, Stanescu-Spinu II, Ilinca R, Balan DG, Balcangiu-Stroescu AE, Mihai DA, Vacaroiu IA, Stefani C, Jinga V. PI3K/AKT/mTOR Dysregulation and Reprogramming Metabolic Pathways in Renal Cancer: Crosstalk with the VHL/HIF Axis. Int J Mol Sci 2023; 24:8391. [PMID: 37176098 PMCID: PMC10179314 DOI: 10.3390/ijms24098391] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 04/26/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023] Open
Abstract
Renal cell carcinoma (RCC) represents 85-95% of kidney cancers and is the most frequent type of renal cancer in adult patients. It accounts for 3% of all cancer cases and is in 7th place among the most frequent histological types of cancer. Clear cell renal cell carcinoma (ccRCC), accounts for 75% of RCCs and has the most kidney cancer-related deaths. One-third of the patients with ccRCC develop metastases. Renal cancer presents cellular alterations in sugars, lipids, amino acids, and nucleic acid metabolism. RCC is characterized by several metabolic dysregulations including oxygen sensing (VHL/HIF pathway), glucose transporters (GLUT 1 and GLUT 4) energy sensing, and energy nutrient sensing cascade. Metabolic reprogramming represents an important characteristic of the cancer cells to survive in nutrient and oxygen-deprived environments, to proliferate and metastasize in different body sites. The phosphoinositide 3-kinase-AKT-mammalian target of the rapamycin (PI3K/AKT/mTOR) signaling pathway is usually dysregulated in various cancer types including renal cancer. This molecular pathway is frequently correlated with tumor growth and survival. The main aim of this review is to present renal cancer types, dysregulation of PI3K/AKT/mTOR signaling pathway members, crosstalk with VHL/HIF axis, and carbohydrates, lipids, and amino acid alterations.
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Affiliation(s)
- Silviu Constantin Badoiu
- Department of Anatomy and Embryology, Faculty of Medicine, Carol Davila University of Medicine and Pharmacy, 8 Eroii Sanitari Blvd, 050474 Bucharest, Romania;
| | - Maria Greabu
- Department of Biochemistry, Faculty of Dentistry, Carol Davila University of Medicine and Pharmacy, 8 Eroii Sanitari Blvd, Sector 5, 050474 Bucharest, Romania;
| | - Daniela Miricescu
- Department of Biochemistry, Faculty of Dentistry, Carol Davila University of Medicine and Pharmacy, 8 Eroii Sanitari Blvd, Sector 5, 050474 Bucharest, Romania;
| | - Iulia-Ioana Stanescu-Spinu
- Department of Biochemistry, Faculty of Dentistry, Carol Davila University of Medicine and Pharmacy, 8 Eroii Sanitari Blvd, Sector 5, 050474 Bucharest, Romania;
| | - Radu Ilinca
- Department of Medical Informatics and Biostatistics, Faculty of Dentistry, Carol Davila University of Medicine and Pharmacy, 8 Eroii Sanitari Blvd, 050474 Bucharest, Romania;
| | - Daniela Gabriela Balan
- Department of Physiology, Faculty of Dentistry, Carol Davila University of Medicine and Pharmacy, 8 Eroii Sanitari Blvd, 050474 Bucharest, Romania; (D.G.B.); (A.-E.B.-S.)
| | - Andra-Elena Balcangiu-Stroescu
- Department of Physiology, Faculty of Dentistry, Carol Davila University of Medicine and Pharmacy, 8 Eroii Sanitari Blvd, 050474 Bucharest, Romania; (D.G.B.); (A.-E.B.-S.)
| | - Doina-Andrada Mihai
- Department of Diabetes, Nutrition and Metabolic Diseases, Faculty of Medicine, Carol Davila University of Medicine and Pharmacy, 8 Eroii Sanitari Blvd, 050474 Bucharest, Romania;
| | - Ileana Adela Vacaroiu
- Department of Nephrology, Faculty of Medicine, Carol Davila University of Medicine and Pharmacy, 020021 Bucharest, Romania;
| | - Constantin Stefani
- Department of Family Medicine and Clinical Base, Dr. Carol Davila Central Military Emergency University Hospital, 134 Calea Plevnei, 010825 Bucharest, Romania;
| | - Viorel Jinga
- Department of Urology, “Prof. Dr. Theodor Burghele” Hospital, 050653 Bucharest, Romania
- “Prof. Dr. Theodor Burghele” Clinical Hospital, University of Medicine and Pharmacy Carol Davila, 050474 Bucharest, Romania
- Medical Sciences Section, Academy of Romanian Scientists, 050085 Bucharest, Romania
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Makhoul C, Houghton FJ, Hinde E, Gleeson PA. Arf5-mediated regulation of mTORC1 at the plasma membrane. Mol Biol Cell 2023; 34:ar23. [PMID: 36735494 PMCID: PMC10092653 DOI: 10.1091/mbc.e22-07-0302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The mechanistic target of rapamycin (mTOR) kinase regulates a major signaling pathway in eukaryotic cells. In addition to regulation of mTORC1 at lysosomes, mTORC1 is also localized at other locations. However, little is known about the recruitment and activation of mTORC1 at nonlysosomal sites. To identify regulators of mTORC1 recruitment to nonlysosomal compartments, novel interacting partners with the mTORC1 subunit, Raptor, were identified using immunoprecipitation and mass spectrometry. We show that one of the interacting partners, Arf5, is a novel regulator of mTORC1 signaling at plasma membrane ruffles. Arf5-GFP localizes with endogenous mTOR at PI3,4P2-enriched membrane ruffles together with the GTPase required for mTORC1 activation, Rheb. Knockdown of Arf5 reduced the recruitment of mTOR to membrane ruffles. The activation of mTORC1 at membrane ruffles was directly demonstrated using a plasma membrane-targeted mTORC1 biosensor, and Arf5 was shown to enhance the phosphorylation of the mTORC1 biosensor substrate. In addition, endogenous Arf5 was shown to be required for rapid activation of mTORC1-mediated S6 phosphorylation following nutrient starvation and refeeding. Our findings reveal a novel Arf5-dependent pathway for recruitment and activation of mTORC1 at plasma membrane ruffles, a process relevant for spatial and temporal regulation of mTORC1 by receptor and nutrient stimuli.
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Affiliation(s)
- Christian Makhoul
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute and
| | - Fiona J Houghton
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute and
| | - Elizabeth Hinde
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute and.,School of Physics, The University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Paul A Gleeson
- Department of Biochemistry and Pharmacology and Bio21 Molecular Science and Biotechnology Institute and
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37
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Regulation of mTORC1 by the Rag GTPases. Biochem Soc Trans 2023; 51:655-664. [PMID: 36929165 DOI: 10.1042/bst20210038] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 02/21/2023] [Accepted: 02/23/2023] [Indexed: 03/18/2023]
Abstract
The Rag GTPases are an evolutionarily conserved family that play a crucial role in amino acid sensing by the mammalian target of rapamycin complex 1 (mTORC1). mTORC1 is often referred to as the master regulator of cell growth. mTORC1 hyperactivation is observed in multiple diseases such as cancer, obesity, metabolic disorders, and neurodegeneration. The Rag GTPases sense amino acid levels and form heterodimers, where RagA or RagB binds to RagC or RagD, to recruit mTORC1 to the lysosome where it becomes activated. Here, we review amino acid signaling to mTORC1 through the Rag GTPases.
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38
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Wada R, Fujinuma S, Nakatsumi H, Matsumoto M, Nakayama KI. Phosphorylation of PBX2, a novel downstream target of mTORC1, is determined by GSK3 and PP1. J Biochem 2023; 173:129-138. [PMID: 36477205 DOI: 10.1093/jb/mvac094] [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: 09/06/2022] [Revised: 11/01/2022] [Accepted: 11/03/2022] [Indexed: 12/12/2022] Open
Abstract
Mechanistic target of rapamycin complex 1 (mTORC1) is a serine-threonine kinase that is activated by extracellular signals, such as nutrients and growth factors. It plays a key role in the control of various biological processes, such as protein synthesis and energy metabolism by mediating or regulating the phosphorylation of multiple target molecules, some of which remain to be identified. We have here reanalysed a large-scale phosphoproteomics data set for mTORC1 target molecules and identified pre-B cell leukemia transcription factor 2 (PBX2) as such a novel target that is dephosphorylated downstream of mTORC1. We confirmed that PBX2, but not other members of the PBX family, is dephosphorylated in an mTORC1 activity-dependent manner. Furthermore, pharmacological and gene knockdown experiments revealed that glycogen synthase kinase 3 (GSK3) and protein phosphatase 1 (PP1) are responsible for the phosphorylation and dephosphorylation of PBX2, respectively. Our results thus suggest that the balance between the antagonistic actions of GSK3 and PP1 determines the phosphorylation status of PBX2 and its regulation by mTORC1.
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Key Words
- glycogen synthase kinase 3 (GSK3)
Abbreviations: DAPI, 4′,6-diamidino-2-phenylindole; DMSO, dimethyl sulfoxide; ERK, extracellular signal–regulated kinase; FOXK1, forkhead box K1;
GSK3, glycogen synthase kinase 3; HA, hemagglutinin; LARP1, La-related protein 1; MEK, ERK kinase; mTORC1, mechanistic target of rapamycin complex 1; PBS, phosphate-buffered saline; PBX2, pre–B cell leukemia transcription factor 2; PI3K, phosphoinositide 3-kinase; PDK1, phosphoinositide-dependent protein kinase 1; PP1, protein phosphatase 1;
PP2A, protein phosphatase 2A; RAG, RAS-related GTP-binding protein; RHEB, Ras homolog enriched in Brain; shRNA, short hairpin RNA; siRNA, small interfering RNA; TBC1D7, TBC1 (TRE2-BUB2-CDC16) domain family member 7; TSC2, tuberous sclerosis complex 2; WT, wild-type
- mechanistic target of rapamycin complex 1 (mTORC1)
- phosphorylation
- pre–B cell leukemia transcription factor 2 (PBX2)
- protein phosphatase 1 (PP1)
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Affiliation(s)
- Reona Wada
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan
| | - Shun Fujinuma
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan
| | - Hirokazu Nakatsumi
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan
| | - Masaki Matsumoto
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan.,Department of Omics and Systems Biology, Graduate School of Medical and Dental Sciences, Niigata University, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata City, Niigata 951-8510, Japan
| | - Keiichi I Nakayama
- Department of Molecular and Cellular Biology, Medical Institute of Bioregulation, Kyushu University, 3-1-1 Maidashi, Higashi-ku, Fukuoka, Fukuoka 812-8582, Japan
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Gareis NC, Rodríguez FM, Cattaneo Moreyra ML, Stassi AF, Angeli E, Etchevers L, Salvetti NR, Ortega HH, Hein GJ, Rey F. Contribution of key elements of nutritional metabolism to the development of cystic ovarian disease in dairy cattle. Theriogenology 2023; 197:209-223. [PMID: 36525860 DOI: 10.1016/j.theriogenology.2022.12.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/28/2022] [Accepted: 12/02/2022] [Indexed: 12/12/2022]
Abstract
The alteration of signaling molecules involved in the general metabolism of animals can negatively influence reproduction. In dairy cattle, the development of follicular cysts and the subsequent appearance of ovarian cystic disease (COD) often lead to decreased reproductive efficiency in the herd. The objective of this review is to summarize the contribution of relevant metabolic and nutritional sensors to the development of COD in dairy cows. In particular, we focus on the study of alterations of the insulin signaling pathway, adiponectin, and other sensors and metabolites relevant to ovarian functionality, which may be related to the development of follicular persistence and follicular formation of cysts in dairy cattle. The results of these studies support the hypothesis that systemic factors could alter the local scenario in the follicle, generating an adverse microenvironment for the resumption of ovarian activity and possibly leading to the persistence of follicles and to the development and recurrence of COD.
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Affiliation(s)
- N C Gareis
- Laboratorio de Biología Celular y Molecular Aplicada, ICiVet-Litoral (UNL-CONICET), Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias - Universidad Nacional del Litoral, Esperanza, Santa Fe, Argentina
| | - F M Rodríguez
- Laboratorio de Biología Celular y Molecular Aplicada, ICiVet-Litoral (UNL-CONICET), Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias - Universidad Nacional del Litoral, Esperanza, Santa Fe, Argentina
| | - M L Cattaneo Moreyra
- Laboratorio de Biología Celular y Molecular Aplicada, ICiVet-Litoral (UNL-CONICET), Esperanza, Santa Fe, Argentina
| | - A F Stassi
- Laboratorio de Biología Celular y Molecular Aplicada, ICiVet-Litoral (UNL-CONICET), Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias - Universidad Nacional del Litoral, Esperanza, Santa Fe, Argentina
| | - E Angeli
- Laboratorio de Biología Celular y Molecular Aplicada, ICiVet-Litoral (UNL-CONICET), Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias - Universidad Nacional del Litoral, Esperanza, Santa Fe, Argentina
| | - L Etchevers
- Laboratorio de Biología Celular y Molecular Aplicada, ICiVet-Litoral (UNL-CONICET), Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias - Universidad Nacional del Litoral, Esperanza, Santa Fe, Argentina
| | - N R Salvetti
- Laboratorio de Biología Celular y Molecular Aplicada, ICiVet-Litoral (UNL-CONICET), Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias - Universidad Nacional del Litoral, Esperanza, Santa Fe, Argentina
| | - H H Ortega
- Laboratorio de Biología Celular y Molecular Aplicada, ICiVet-Litoral (UNL-CONICET), Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias - Universidad Nacional del Litoral, Esperanza, Santa Fe, Argentina
| | - G J Hein
- Laboratorio de Biología Celular y Molecular Aplicada, ICiVet-Litoral (UNL-CONICET), Esperanza, Santa Fe, Argentina; Centro Universitario Gálvez (CUG-UNL), Gálvez, Santa Fe, Argentina
| | - F Rey
- Laboratorio de Biología Celular y Molecular Aplicada, ICiVet-Litoral (UNL-CONICET), Esperanza, Santa Fe, Argentina; Facultad de Ciencias Veterinarias - Universidad Nacional del Litoral, Esperanza, Santa Fe, Argentina.
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40
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Sun Y, Wang H, Qu T, Luo J, An P, Ren F, Luo Y, Li Y. mTORC2: a multifaceted regulator of autophagy. Cell Commun Signal 2023; 21:4. [PMID: 36604720 PMCID: PMC9814435 DOI: 10.1186/s12964-022-00859-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 03/06/2022] [Indexed: 01/06/2023] Open
Abstract
Autophagy is a multi-step catabolic process that delivers cellular components to lysosomes for degradation and recycling. The dysregulation of this precisely controlled process disrupts cellular homeostasis and leads to many pathophysiological conditions. The mechanistic target of rapamycin (mTOR) is a central nutrient sensor that integrates growth signals with anabolism to fulfil biosynthetic and bioenergetic requirements. mTOR nucleates two distinct evolutionarily conserved complexes (mTORC1 and mTORC2). However, only mTORC1 is acutely inhibited by rapamycin. Consequently, mTORC1 is a well characterized regulator of autophagy. While less is known about mTORC2, the availability of acute small molecule inhibitors and multiple genetic models has led to increased understanding about the role of mTORC2 in autophagy. Emerging evidence suggests that the regulation of mTORC2 in autophagy is mainly through its downstream effector proteins, and is variable under different conditions and cellular contexts. Here, we review recent advances that describe a role for mTORC2 in this catabolic process, and propose that mTORC2 could be a potential clinical target for the treatment of autophagy-related diseases. Video abstract.
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Affiliation(s)
- Yanan Sun
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083 China
| | - Huihui Wang
- grid.411734.40000 0004 1798 5176College of Food Science and Engineering, Gansu Agricultural University, Lanzhou, 730070 China
| | - Taiqi Qu
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083 China
| | - Junjie Luo
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083 China
| | - Peng An
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083 China
| | - Fazheng Ren
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083 China
| | - Yongting Luo
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083 China
| | - Yixuan Li
- grid.22935.3f0000 0004 0530 8290Key Laboratory of Precision Nutrition and Food Quality, Department of Nutrition and Health, China Agricultural University, Beijing, 100083 China
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41
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Jordan JT, Orr CC, Thalheimer RD, Cambillo JV, Beauchamp RL, Shaikh G, Muzikansky A, Stemmer-Rachamimov A, Giovannini M, Kalamarides M, Barker FG, Ramesh V, Plotkin SR. Prospective phase II trial of the dual mTORC1/2 inhibitor vistusertib for progressive or symptomatic meningiomas in persons with neurofibromatosis 2. Neurooncol Adv 2023; 5:vdad041. [PMID: 37215956 PMCID: PMC10195194 DOI: 10.1093/noajnl/vdad041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/24/2023] Open
Abstract
Background Meningiomas occur in 80% of persons with neurofibromatosis 2 (NF2) and cause significant mortality and morbidity, yet there are no effective medical treatments. NF2-deficient tumors have constitutive activation of mammalian/mechanistic target of rapamycin (mTOR), and treatment with mTORC1 inhibitors results in growth arrest in a minority of tumors, with paradoxical activation of the mTORC2/AKT pathway. We studied the effect of vistusertib, a dual mTORC1/mTORC2 inhibitor, in NF2 patients with progressive or symptomatic meningiomas. Methods Vistusertib was administered orally at 125 mg twice daily for 2 consecutive days each week. The primary endpoint was the imaging response in the target meningioma, defined as a volume decrease of 20% compared with the baseline. Secondary endpoints included toxicity, imaging response of nontarget tumors, quality of life, and genetic biomarkers. Results Eighteen participants (13 female), median age of 41 (range, 18-61) years, were enrolled. In target meningiomas, the best response was partial response (PR) in 1/18 tumors (6%) and stable disease (SD) in 17/18 tumors (94%). For all measured intracranial meningiomas and vestibular schwannomas, the best imaging response was PR in 6/59 tumors (10%) and SD in 53 (90%). Treatment-related grade 3/4 adverse events occurred in 14 (78%) participants, and 9 participants discontinued treatment due to side effects. Conclusions Although the study did not meet the primary endpoint, vistusertib treatment was associated with high rates of SD in progressive NF2-related tumors. However, this dosing regimen for vistusertib was poorly tolerated. Future studies of dual mTORC inhibitors for NF2 should focus on optimizing tolerability and evaluating the relevance of tumor stability in participants.
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Affiliation(s)
- Justin T Jordan
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Christina C Orr
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Raquel D Thalheimer
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Josephine V Cambillo
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Roberta L Beauchamp
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Ghalib Shaikh
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Alona Muzikansky
- Biostatistics Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Anat Stemmer-Rachamimov
- Department of Pathology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Marco Giovannini
- Department of Head and Neck Surgery, David Geffen School of Medicine at UCLA and Jonsson Comprehensive Cancer Center (JCCC), University of California Los Angeles, Los Angeles, CA, USA
| | - Michel Kalamarides
- Department of Neurosurgery, Hopital Pitie-Salpetriere, Sorbonne Université, Paris, France
| | - Fred G Barker
- Neurosurgical Service, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Vijaya Ramesh
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
- Center for Genomic Medicine, Massachusetts General Hospital, Boston, MA, USA
| | - Scott R Plotkin
- Corresponding Author: Scott R. Plotkin, MD, PhD, Department of Neurology, Division of Neuro-Oncology, Massachusetts General Hospital Cancer Center, Harvard Medical School, 55 Fruit Street, Yawkey 9E, Boston, MA 02114, USA ()
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Kunishige R, Murata M, Kano F. Targeted protein degradation by Trim-Away using cell resealing coupled with microscopic image-based quantitative analysis. Front Cell Dev Biol 2022; 10:1027043. [PMID: 36601537 PMCID: PMC9806799 DOI: 10.3389/fcell.2022.1027043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Accepted: 11/28/2022] [Indexed: 12/23/2022] Open
Abstract
"Trim-Away" technology enables rapid degradation of endogenous proteins without prior modification of protein-coding genes or mRNAs through delivery of antibodies that target proteins of interest. Although this approach can be readily applied to almost any cytosolic protein, strategies for cytosolic antibody delivery have been limited to microinjection or electroporation, which require skill-dependent operation or specialized equipment. Thus, the development of antibody delivery methods that are convenient, scalable, and preferably do not require detachment of adherent cells is required to extend the versatility of the Trim-Away method. Here, we developed a cell resealing technique optimized for Trim-Away degradation, which uses the pore-forming toxin streptolysin O (SLO) to permeabilize the cell membrane and delivered the antibodies of interest into HEK293T, HeLa, and HK-2 cell lines. We demonstrated the ability of Trim-Away protein degradation using IKKα and mTOR as targets, and we showed the availability of the developed system in antibody screening for the Trim-Away method. Furthermore, we effectively coupled Trim-Away with cyclic immunofluorescence and microscopic image-based analysis, which enables single-cell multiplexed imaging analysis. Taking advantage of this new analysis strategy, we were able to compensate for low signal-to-noise due to cell-to-cell variation, which occurs in the Trim-Away method because of the heterogenous contents of the introduced antibody, target protein, and TRIM21 in individual cells. Therefore, the reported cell resealing technique coupled with microscopic image analysis enables Trim-Away users to elucidate target protein function and the effects of target protein degradation on various cellular functions in a more quantitative and precise manner.
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Affiliation(s)
- Rina Kunishige
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan,Multimodal Cell Analysis Collaborative Research Cluster, Tokyo Institute of Technology, Yokohama, Japan
| | - Masayuki Murata
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan,Multimodal Cell Analysis Collaborative Research Cluster, Tokyo Institute of Technology, Yokohama, Japan,International Research Center for Neurointelligence, Institutes for Advanced Study, The University of Tokyo, Tokyo, Japan
| | - Fumi Kano
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan,Multimodal Cell Analysis Collaborative Research Cluster, Tokyo Institute of Technology, Yokohama, Japan,*Correspondence: Fumi Kano,
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Wainstein E, Maik-Rachline G, Blenis J, Seger R. AKTs do not translocate to the nucleus upon stimulation but AKT3 can constitutively signal from the nuclear envelope. Cell Rep 2022; 41:111733. [PMID: 36476861 DOI: 10.1016/j.celrep.2022.111733] [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: 04/19/2022] [Revised: 08/23/2022] [Accepted: 11/04/2022] [Indexed: 12/12/2022] Open
Abstract
AKT is a central signaling protein kinase that plays a role in the regulation of cellular survival metabolism and cell growth, as well as in pathologies such as diabetes and cancer. Human AKT consists of three isoforms (AKT1-3) that may fulfill different functions. Here, we report that distinct subcellular localization of the isoforms directly influences their activity and function. AKT1 is localized primarily in the cytoplasm, AKT2 in the nucleus, and AKT3 in the nucleus or nuclear envelope. None of the isoforms actively translocates into the nucleus upon stimulation. Interestingly, AKT3 at the nuclear envelope is constitutively phosphorylated, enabling a constant phosphorylation of TSC2 at this location. Knockdown of AKT3 induces moderate attenuation of cell proliferation of breast cancer cells. We suggest that in addition to the stimulation-induced activation of the lysosomal/cytoplasmic AKT1-TSC2 pathway, a subpopulation of TSC2 is constitutively inactivated by AKT3 at the nuclear envelope of transformed cells.
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Affiliation(s)
- Ehud Wainstein
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Galia Maik-Rachline
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - John Blenis
- Meyer Cancer Center and Department of Pharmacology, Weill Cornell Medical College, New York, NY 10021, USA
| | - Rony Seger
- Department of Immunology and Regenerative Biology, Weizmann Institute of Science, Rehovot 7610001, Israel.
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Kahilainen A, Oostra V, Somervuo P, Minard G, Saastamoinen M. Alternative developmental and transcriptomic responses to host plant water limitation in a butterfly metapopulation. Mol Ecol 2022; 31:5666-5683. [PMID: 34516691 DOI: 10.1111/mec.16178] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 08/06/2021] [Accepted: 09/02/2021] [Indexed: 01/13/2023]
Abstract
Predicting how climate change affects biotic interactions poses a challenge. Plant-insect herbivore interactions are particularly sensitive to climate change, as climate-induced changes in plant quality cascade into the performance of insect herbivores. Whereas the immediate survival of herbivore individuals depends on plastic responses to climate change-induced nutritional stress, long-term population persistence via evolutionary adaptation requires genetic variation for these responses. To assess the prospects for population persistence under climate change, it is therefore crucial to characterize response mechanisms to climate change-induced stressors, and quantify their variability in natural populations. Here, we test developmental and transcriptomic responses to water limitation-induced host plant quality change in a Glanville fritillary butterfly (Melitaea cinxia) metapopulation. We combine nuclear magnetic resonance spectroscopy on the plant metabolome, larval developmental assays and an RNA sequencing analysis of the larval transcriptome. We observed that responses to feeding on water-limited plants, in which amino acids and aromatic compounds are enriched, showed marked variation within the metapopulation, with individuals of some families performing better on control and others on water-limited plants. The transcriptomic responses were concordant with the developmental responses: families exhibiting opposite developmental responses also produced opposite transcriptomic responses (e.g. in growth-associated transcripts). The divergent responses in both larval development and transcriptome are associated with differences between families in amino acid catabolism and storage protein production. The results reveal intrapopulation variability in plasticity, suggesting that the Finnish M. cinxia metapopulation harbours potential for buffering against drought-induced changes in host plant quality.
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Affiliation(s)
- Aapo Kahilainen
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, P.O. Box 65, Helsinki, FIN-00014, Finland
| | - Vicencio Oostra
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, P.O. Box 65, Helsinki, FIN-00014, Finland.,Department of Evolution, Ecology and Behaviour, University of Liverpool, Crown Street, Liverpool, L69 7ZB, United Kingdom
| | - Panu Somervuo
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, P.O. Box 65, Helsinki, FIN-00014, Finland
| | - Guillaume Minard
- Univ Lyon, Université Claude Bernard Lyon 1, CNRS, INRAe, VetAgro Sup, UMR Ecologie Microbienne, Villeurbanne, France
| | - Marjo Saastamoinen
- Organismal and Evolutionary Biology Research Programme, University of Helsinki, P.O. Box 65, Helsinki, FIN-00014, Finland.,Helsinki Institute of Life Science, University of Helsinki, Finland
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Helfenberger KE, Argentino GF, Benzo Y, Herrera LM, Finocchietto P, Poderoso C. Angiotensin II Regulates Mitochondrial mTOR Pathway Activity Dependent on Acyl-CoA Synthetase 4 in Adrenocortical Cells. Endocrinology 2022; 163:6763139. [PMID: 36256598 DOI: 10.1210/endocr/bqac170] [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] [Received: 07/08/2022] [Indexed: 11/19/2022]
Abstract
Two well-known protein complexes in mammalian cells, mTOR type 1 and type 2 (mTORC1/2) are involved in several cellular processes such as protein synthesis, cell proliferation, and commonly dysregulated in cancer. An acyl-CoA synthetase type 4 (ACSL4) is one of the most recently mTORC1/2 regulators described, in breast cancer cells. The expression of ACSL4 is hormone-regulated in adrenocortical cells and required for steroid biosynthesis. mTORC1/2 have been reported to be crucial in the proliferation of human adrenocortical tumor cells H295R and interestingly reported at several subcellular locations, which has brought cell biology to the vanguard of the mTOR signaling field. In the present work, we study the regulation of mTORC1/2 activation by angiotensin II (Ang II)-the trophic hormone for adrenocortical cells-the subcellular localization of mTORC1/2 signaling proteins and the role of ACSL4 in the regulation of this pathway, in H295R cells. Ang II promotes activation by phosphorylation of mTORC1/2 pathway proteins in a time-dependent manner. Mitochondrial pools of ribosomal protein S6, protein kinase B (Akt) in threonine 308, and serine 473 and Rictor are phosphorylated and activated. Glycogen synthase kinase type 3 (GSK3) is phosphorylated and inactivated in mitochondria, favoring mTORC1 activation. Epidermal growth factor, a classic mTORC1/2 activator, promoted unique activation kinetics of mTORC1/2 pathway, except for Akt phosphorylation. Here, we demonstrate that ACSL4 is necessary for mTORC1/2 effectors phosphorylation and H295R proliferation, triggered by Ang II. Ang II promotes activation of mitochondrial mTORC1/2 signaling proteins, through ACSL4, with a direct effect on adrenocortical cellular proliferation.
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Affiliation(s)
- Katia E Helfenberger
- Departamento de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires C1121ABG, Argentina
- Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires-CONICET, Buenos Aires C1121ABG, Argentina
| | - Giuliana F Argentino
- Departamento de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires C1121ABG, Argentina
- Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires-CONICET, Buenos Aires C1121ABG, Argentina
| | - Yanina Benzo
- Departamento de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires C1121ABG, Argentina
- Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires-CONICET, Buenos Aires C1121ABG, Argentina
| | - Lucía M Herrera
- Departamento de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires C1121ABG, Argentina
- Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires-CONICET, Buenos Aires C1121ABG, Argentina
| | - Paola Finocchietto
- Laboratorio del Metabolismo del Oxígeno. Hospital de Clínicas "José de San Martín," Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires C1121ABG, Argentina
- Instituto de Inmunología, Genética y Metabolismo (INIGEM), Universidad de Buenos Aires-CONICET, Buenos Aires C1121ABG, Argentina
| | - Cecilia Poderoso
- Departamento de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires C1121ABG, Argentina
- Instituto de Investigaciones Biomédicas (INBIOMED), Universidad de Buenos Aires-CONICET, Buenos Aires C1121ABG, Argentina
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Hatipoglu A, Menon D, Levy T, Frias MA, Foster DA. Inhibiting glutamine utilization creates a synthetic lethality for suppression of ATP citrate lyase in KRas-driven cancer cells. PLoS One 2022; 17:e0276579. [PMID: 36269753 PMCID: PMC9586366 DOI: 10.1371/journal.pone.0276579] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Accepted: 10/10/2022] [Indexed: 11/16/2022] Open
Abstract
Metabolic reprogramming is now considered a hallmark of cancer cells. KRas-driven cancer cells use glutaminolysis to generate the tricarboxylic acid cycle intermediate α-ketoglutarate via a transamination reaction between glutamate and oxaloacetate. We reported previously that exogenously supplied unsaturated fatty acids could be used to synthesize phosphatidic acid-a lipid second messenger that activates both mammalian target of rapamycin (mTOR) complex 1 (mTORC1) and mTOR complex 2 (mTORC2). A key target of mTORC2 is Akt-a kinase that promotes survival and regulates cell metabolism. We report here that mono-unsaturated oleic acid stimulates the phosphorylation of ATP citrate lyase (ACLY) at the Akt phosphorylation site at S455 in an mTORC2 dependent manner. Inhibition of ACLY in KRas-driven cancer cells in the absence of serum resulted in loss of cell viability. We examined the impact of glutamine (Gln) deprivation in combination with inhibition of ACLY on the viability of KRas-driven cancer cells. While Gln deprivation was somewhat toxic to KRas-driven cancer cells by itself, addition of the ACLY inhibitor SB-204990 increased the loss of cell viability. However, the transaminase inhibitor aminooxyacetate was minimally toxic and the combination of SB-204990 and aminooxtacetate led to significant loss of cell viability and strong cleavage of poly-ADP ribose polymerase-indicating apoptotic cell death. This effect was not observed in MCF7 breast cancer cells that do not have a KRas mutation or in BJ-hTERT human fibroblasts which have no oncogenic mutation. These data reveal a synthetic lethality between inhibition of glutamate oxaloacetate transaminase and ACLY inhibition that is specific for KRas-driven cancer cells and the apparent metabolic reprogramming induced by activating mutations to KRas.
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Affiliation(s)
- Ahmet Hatipoglu
- Department of Biological Sciences, Hunter College of the City University of New York, New York, New York, United States of America
- Biochemistry Program, Graduate Center of the City University of New York, New York, New York, United States of America
| | - Deepak Menon
- Department of Biological Sciences, Hunter College of the City University of New York, New York, New York, United States of America
- Biochemistry Program, Graduate Center of the City University of New York, New York, New York, United States of America
| | - Talia Levy
- Department of Biological Sciences, Hunter College of the City University of New York, New York, New York, United States of America
| | - Maria A. Frias
- Department of Biological Sciences, Hunter College of the City University of New York, New York, New York, United States of America
- Department of Biology and Health Promotion, St Francis College, Brooklyn, New York, New York, United States of America
| | - David A. Foster
- Department of Biological Sciences, Hunter College of the City University of New York, New York, New York, United States of America
- Biochemistry Program, Graduate Center of the City University of New York, New York, New York, United States of America
- Biology Program, Graduate Center of the City University of New York, New York, New York, United States of America
- Department of Pharmacology, Weill Cornell Medicine, New York, New York, United States of America
- * E-mail:
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Jiang W, Ou Z, Zhu Q, Zai H. RagC GTPase regulates mTOR to promote chemoresistance in senescence-like HepG2 cells. Front Physiol 2022; 13:949737. [PMID: 36267578 PMCID: PMC9577253 DOI: 10.3389/fphys.2022.949737] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Accepted: 09/20/2022] [Indexed: 11/23/2022] Open
Abstract
Radiotherapy and chemotherapy can arrest cancer cells in a senescence-like state, which can lead to therapy resistance and cancer relapse. mTOR is hyperactivated in senescent cells but the mechanisms remain unclear. In this study, we examine the roles of several mTOR-regulated GTPases in senescence-like liver cancer cells and the mechanisms in drug resistance. We show that although RagC, Rheb, Rab1A, Rab5 and Arf1 GTPases were required for optimal mTOR activation in proliferating HepG2 cells, only RagC and Rheb are required in the senescence-like counterparts. Consistently, the drug resistance of the senescence-like HepG2 can be reduced by knocking down RagC and Rheb but not the other GTPases. Autophagic and lysosomal activity were increased in senescence-like cells; pharmacological inhibition of autophagy-lysosome decreased mTOR activity and preferentially sensitized senescence-like HepG2 cells to chemotherapy drugs including trametinib, cisplatin, and doxorubicin. In liver cancer patients, expression of RagC and Rheb but not other GTPases examined was associated with unfavorable prognosis. Our study therefore has defined a key role of Rag-Rheb GTPase in mediating mTOR activation and drug resistance in senescence-like HepG2 cells, which could have important implications in developing second-line treatments for liver cancer patients.
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Affiliation(s)
- Wei Jiang
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, Hunan, China
| | - Zhenglin Ou
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, Hunan, China
| | - Qin Zhu
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, Hunan, China
| | - Hongyan Zai
- Department of General Surgery, Xiangya Hospital, Central South University, Changsha, Hunan, China
- National Clinical Research Center for Geriatric Disorders, Central South University, Changsha, Hunan, China
- *Correspondence: Hongyan Zai,
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Oncolytic Avian Reovirus p17-Modulated Inhibition of mTORC1 by Enhancement of Endogenous mTORC1 Inhibitors Binding to mTORC1 To Disrupt Its Assembly and Accumulation on Lysosomes. J Virol 2022; 96:e0083622. [PMID: 35946936 PMCID: PMC9472607 DOI: 10.1128/jvi.00836-22] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The mechanism by which avian reovirus (ARV)-modulated suppression of mTORC1 triggers autophagy remains largely unknown. In this work, we determined that p17 functions as a negative regulator of mTORC1. This study suggest novel mechanisms whereby p17-modulated inhibition of mTORC1 occurs via upregulation of p53, inactivation of Akt, and enhancement of binding of the endogenous mTORC1 inhibitors (PRAS40, FKBP38, and FKPP12) to mTORC1 to disrupt its assembly and accumulation on lysosomes. p17-modulated inhibition of Akt leads to activation of the downstream targets PRAS40 and TSC2, which results in mTORC1 inhibition, thereby triggering autophagy and translation shutoff, which is favorable for virus replication. p17 impairs the interaction of mTORC1 with its activator Rheb, which promotes FKBP38 interaction with mTORC1. It is worth noting that p17 activates ULK1 and Beclin1 and increases the formation of the Beclin 1/class III PI3K complex. These effects could be reversed in the presence of insulin or depletion of p53. Furthermore, we found that p17 induces autophagy in cancer cell lines by upregulating the p53/PTEN pathway, which inactivates Akt and mTORC1. This study highlights p17-modulated inhibition of Akt and mTORC1, which triggers autophagy and translation shutoff by positively modulating the tumor suppressors p53 and TSC2 and endogenous mTORC1 inhibitors. IMPORTANCE The mechanisms by which p17-modulated inhibition of mTORC1 induces autophagy and translation shutoff is elucidated. In this work, we determined that p17 serves as a negative regulator of mTORC1. This study provides several lines of conclusive evidence demonstrating that p17-modulated inhibition of mTORC1 occurs via upregulation of the p53/PTEN pathway, downregulation of the Akt/Rheb/mTORC1 pathway, enhancement of binding of the endogenous mTORC1 inhibitors to mTORC1 to disrupt its assembly, and suppression of mTORC1 accumulation on lysosomes. This work provides valuable information for better insights into p17-modulated inhibition of mTORC1, which induces autophagy and translation shutoff to benefit virus replication.
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Fedorova O, Parfenyev S, Daks A, Shuvalov O, Barlev NA. The Role of PTEN in Epithelial–Mesenchymal Transition. Cancers (Basel) 2022; 14:cancers14153786. [PMID: 35954450 PMCID: PMC9367281 DOI: 10.3390/cancers14153786] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2022] [Revised: 07/31/2022] [Accepted: 08/02/2022] [Indexed: 11/23/2022] Open
Abstract
Simple Summary The PTEN phosphatase is a ubiquitously expressed tumor suppressor, which inhibits the PI3K/AKT pathway in the cell. The PI3K/AKT pathway is considered to be one of the main signaling pathways that drives the proliferation of cancer cells. Furthermore, the same pathway controls the epithelial–mesenchymal transition (EMT). EMT is an evolutionarily conserved developmental program, which, upon aberrant reactivation, is also involved in the formation of cancer metastases. Importantly, metastasis is the leading cause of cancer-associated deaths. In this review, we discuss the literature data that highlight the role of PTEN in EMT. Based on this knowledge, we speculate about new possible strategies for cancer treatment. Abstract Phosphatase and Tensin Homolog deleted on Chromosome 10 (PTEN) is one of the critical tumor suppressor genes and the main negative regulator of the PI3K pathway. PTEN is frequently found to be inactivated, either partially or fully, in various malignancies. The PI3K/AKT pathway is considered to be one of the main signaling cues that drives the proliferation of cells. Perhaps it is not surprising, then, that this pathway is hyperactivated in highly proliferative tumors. Importantly, the PI3K/AKT pathway also coordinates the epithelial–mesenchymal transition (EMT), which is pivotal for the initiation of metastases and hence is regarded as an attractive target for the treatment of metastatic cancer. It was shown that PTEN suppresses EMT, although the exact mechanism of this effect is still not fully understood. This review is an attempt to systematize the published information on the role of PTEN in the development of malignant tumors, with a main focus on the regulation of the PI3K/AKT pathway in EMT.
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Mortazavi M, Moosavi F, Martini M, Giovannetti E, Firuzi O. Prospects of targeting PI3K/AKT/mTOR pathway in pancreatic cancer. Crit Rev Oncol Hematol 2022; 176:103749. [PMID: 35728737 DOI: 10.1016/j.critrevonc.2022.103749] [Citation(s) in RCA: 45] [Impact Index Per Article: 22.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 06/11/2022] [Accepted: 06/16/2022] [Indexed: 02/07/2023] Open
Abstract
Pancreatic ductal adenocarcinoma (PDAC) has one of the worst prognoses among all malignancies. PI3K/AKT/mTOR signaling pathway, a main downstream effector of KRAS is involved in the regulation of key hallmarks of cancer. We here report that whole-genome analyses demonstrate the frequent involvement of aberrant activations of PI3K/AKT/mTOR pathway components in PDAC patients and critically evaluate preclinical and clinical evidence on the application of PI3K/AKT/mTOR pathway targeting agents. Combinations of these agents with chemotherapeutics or other targeted therapies, including the modulators of cyclin-dependent kinases, receptor tyrosine kinases and RAF/MEK/ERK pathway are also examined. Although human genetic studies and preclinical pharmacological investigations have provided strong evidence on the role of PI3K/AKT/mTOR pathway in PDAC, clinical studies in general have not been as promising. Patient stratification seems to be the key missing point and with the advent of biomarker-guided clinical trials, targeting PI3K/AKT/mTOR pathway could provide valuable assets for treatment of pancreatic cancer patients.
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Affiliation(s)
- Motahareh Mortazavi
- Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Fatemeh Moosavi
- Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
| | - Miriam Martini
- Department of Molecular Biotechnology and Health Sciences, University of Torino, Turin, Italy
| | - Elisa Giovannetti
- Department of Medical Oncology, Cancer Center Amsterdam, Amsterdam UMC, VU University Medical Center (VUmc), Amsterdam, the Netherlands; Cancer Pharmacology Lab, Fondazine Pisana per la Scienza, Pisa, Italy
| | - Omidreza Firuzi
- Medicinal and Natural Products Chemistry Research Center, Shiraz University of Medical Sciences, Shiraz, Iran.
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