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Chen X, Chen Z, Li M, Guo W, Yuan S, Xu L, Lin C, Shi X, Chen W, Yang S. Tranylcypromine upregulates Sestrin 2 expression to ameliorate NLRP3-related noise-induced hearing loss. Neural Regen Res 2025; 20:1483-1494. [PMID: 39075914 DOI: 10.4103/nrr.nrr-d-24-00130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 05/21/2024] [Indexed: 07/31/2024] Open
Abstract
JOURNAL/nrgr/04.03/01300535-202505000-00030/figure1/v/2024-07-28T173839Z/r/image-tiff Noise-induced hearing loss is the primary non-genetic factor contributing to auditory dysfunction. However, there are currently no effective pharmacological interventions for patients with noise-induced hearing loss. Here, we present evidence suggesting that the lysine-specific demethylase 1 inhibitor-tranylcypromine is an otoprotective agent that could be used to treat noise-induced hearing loss, and elucidate its underlying regulatory mechanisms. We established a mouse model of permanent threshold shift hearing loss by exposing the mice to white broadband noise at a sound pressure level of 120 dB for 4 hours. We found that tranylcypromine treatment led to the upregulation of Sestrin2 (SESN2) and activation of the autophagy markers light chain 3B and lysosome-associated membrane glycoprotein 1 in the cochleae of mice treated with tranylcypromine. The noise exposure group treated with tranylcypromine showed significantly lower average auditory brainstem response hearing thresholds at click, 4, 8, and 16 kHz frequencies compared with the noise exposure group treated with saline. These findings indicate that tranylcypromine treatment resulted in increased SESN2, light chain 3B, and lysosome-associated membrane glycoprotein 1 expression after noise exposure, leading to a reduction in levels of 4-hydroxynonenal and cleaved caspase-3, thereby reducing noise-induced hair cell loss. Additionally, immunoblot analysis demonstrated that treatment with tranylcypromine upregulated SESN2 expression via the autophagy pathway. Tranylcypromine treatment also reduced the production of NOD-like receptor family pyrin domain-containing 3 (NLRP3) production. In conclusion, our results showed that tranylcypromine treatment ameliorated cochlear inflammation by promoting the expression of SESN2, which induced autophagy, thereby restricting NLRP3-related inflammasome signaling, alleviating cochlear hair cell loss, and protecting hearing function. These findings suggest that inhibiting lysine-specific demethylase 1 is a potential therapeutic strategy for preventing hair cell loss and noise-induced hearing loss.
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Affiliation(s)
- Xihang Chen
- Senior Department of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian Province, China
| | - Zhifeng Chen
- Senior Department of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
- Department of Otolaryngology Head and Neck Surgery, The 940 Hospital of Joint Logistics Support Force of Chinese PLA, Lanzhou, Gansu Province, China
| | - Menghua Li
- Senior Department of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
| | - Weiwei Guo
- Senior Department of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
| | - Shuolong Yuan
- Senior Department of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
| | - Liangwei Xu
- Senior Department of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
| | - Chang Lin
- Department of Otorhinolaryngology Head and Neck Surgery, The First Affiliated Hospital of Fujian Medical University, Fuzhou, Fujian Province, China
| | - Xi Shi
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Pharmaceutical Sciences, Hainan University, Haikou, Hainan Province, China
- Academician Workstation of Hainan University, School of Pharmaceutical Sciences, Yazhou Bay, Sanya, Hainan Province, China
| | - Wei Chen
- Senior Department of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
| | - Shiming Yang
- Senior Department of Otolaryngology Head and Neck Surgery, Chinese PLA General Hospital, Chinese PLA Medical School, Beijing, China
- State Key Laboratory of Hearing and Balance Science, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Beijing, China
- Key Laboratory of Hearing Science, Ministry of Education, Beijing, China
- Beijing Key Laboratory of Hearing Impairment Prevention and Treatment, Beijing, China
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Hejazian SM, Pirmoradi S, Zununi Vahed S, Kumar Roy R, Hosseiniyan Khatibi SM. An update on Glycerophosphodiester Phosphodiesterases; From Bacteria to Human. Protein J 2024; 43:187-199. [PMID: 38491249 DOI: 10.1007/s10930-024-10190-4] [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] [Accepted: 02/29/2024] [Indexed: 03/18/2024]
Abstract
The hydrolysis of deacylated glycerophospholipids into sn-glycerol 3-phosphate and alcohol is facilitated by evolutionarily conserved proteins known as glycerophosphodiester phosphodiesterases (GDPDs). These proteins are crucial for the pathogenicity of bacteria and for bioremediation processes aimed at degrading organophosphorus esters that pose a hazard to both humans and the environment. Additionally, GDPDs are enzymes that respond to multiple nutrients and could potentially serve as candidate genes for addressing deficiencies in zinc, iron, potassium, and especially phosphate in important plants like rice. In mammals, glycerophosphodiesterases (GDEs) play a role in regulating osmolytes, facilitating the biosynthesis of anandamine, contributing to the development of skeletal muscle, promoting the differentiation of neurons and osteoblasts, and influencing pathological states. Due to their capacity to enhance a plant's ability to tolerate various nutrient deficiencies and their potential as pharmaceutical targets in humans, GDPDs have received increased attention in recent times. This review provides an overview of the functions of GDPD families as vital and resilient enzymes that regulate various pathways in bacteria, plants, and humans.
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Affiliation(s)
| | - Saeed Pirmoradi
- Clinical Research Development Unit of Tabriz Valiasr Hospital, Tabriz University of Medical Sciences, Tabriz, Iran
- Faculty of Electrical Engineering, K.N. Toosi University of Technology, Tehran, Iran
| | | | | | - Seyed Mahdi Hosseiniyan Khatibi
- Kidney Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
- Clinical Research Development Unit of Tabriz Valiasr Hospital, Tabriz University of Medical Sciences, Tabriz, Iran.
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Warren B, Eberl D. What can insects teach us about hearing loss? J Physiol 2024; 602:297-316. [PMID: 38128023 DOI: 10.1113/jp281281] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Accepted: 12/05/2023] [Indexed: 12/23/2023] Open
Abstract
Over the last three decades, insects have been utilized to provide a deep and fundamental understanding of many human diseases and disorders. Here, we present arguments for insects as models to understand general principles underlying hearing loss. Despite ∼600 million years since the last common ancestor of vertebrates and invertebrates, we share an overwhelming degree of genetic homology particularly with respect to auditory organ development and maintenance. Despite the anatomical differences between human and insect auditory organs, both share physiological principles of operation. We explain why these observations are expected and highlight areas in hearing loss research in which insects can provide insight. We start by briefly introducing the evolutionary journey of auditory organs, the reasons for using insect auditory organs for hearing loss research, and the tools and approaches available in insects. Then, the first half of the review focuses on auditory development and auditory disorders with a genetic cause. The second half analyses the physiological and genetic consequences of ageing and short- and long-term changes as a result of noise exposure. We finish with complex age and noise interactions in auditory systems. In this review, we present some of the evidence and arguments to support the use of insects to study mechanisms and potential treatments for hearing loss in humans. Obviously, insects cannot fully substitute for all aspects of human auditory function and loss of function, although there are many important questions that can be addressed in an animal model for which there are important ethical, practical and experimental advantages.
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Affiliation(s)
- Ben Warren
- Neurogenetics Group, College of Life Sciences, University of Leicester, Leicester, UK
| | - Daniel Eberl
- Department of Biology, University of Iowa, Iowa City, IA, USA
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Delaney DS, Liew LJ, Lye J, Atlas MD, Wong EYM. Overcoming barriers: a review on innovations in drug delivery to the middle and inner ear. Front Pharmacol 2023; 14:1207141. [PMID: 37927600 PMCID: PMC10620978 DOI: 10.3389/fphar.2023.1207141] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 10/02/2023] [Indexed: 11/07/2023] Open
Abstract
Despite significant advances in the development of therapeutics for hearing loss, drug delivery to the middle and inner ear remains a challenge. As conventional oral or intravascular administration are ineffective due to poor bioavailability and impermeability of the blood-labyrinth-barrier, localized delivery is becoming a preferable approach for certain drugs. Even then, localized delivery to the ear precludes continual drug delivery due to the invasive and potentially traumatic procedures required to access the middle and inner ear. To address this, the preclinical development of controlled release therapeutics and drug delivery devices have greatly advanced, with some now showing promise clinically. This review will discuss the existing challenges in drug development for treating the most prevalent and damaging hearing disorders, in particular otitis media, perforation of the tympanic membrane, cholesteatoma and sensorineural hearing loss. We will then address novel developments in drug delivery that address these including novel controlled release therapeutics such as hydrogel and nanotechnology and finally, novel device delivery approaches such as microfluidic systems and cochlear prosthesis-mediated delivery. The aim of this review is to investigate how drugs can reach the middle and inner ear more efficiently and how recent innovations could be applied in aiding drug delivery in certain pathologic contexts.
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Affiliation(s)
- Derek S. Delaney
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA, Australia
- Faculty of Health Sciences, Curtin Health Innovation Research Institute, Curtin University, Bentley, WA, Australia
| | - Lawrence J. Liew
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA, Australia
- Centre for Ear Sciences, Medical School, The University of Western Australia, Nedlands, WA, Australia
| | - Joey Lye
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA, Australia
| | - Marcus D. Atlas
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA, Australia
- Centre for Ear Sciences, Medical School, The University of Western Australia, Nedlands, WA, Australia
- Faculty of Health Sciences, Curtin Medical School, Curtin University, Bentley, WA, Australia
| | - Elaine Y. M. Wong
- Hearing Therapeutics, Ear Science Institute Australia, Nedlands, WA, Australia
- Centre for Ear Sciences, Medical School, The University of Western Australia, Nedlands, WA, Australia
- Faculty of Health Sciences, Curtin Medical School, Curtin University, Bentley, WA, Australia
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Na D, Zhang J, Beaulac HJ, Piekna-Przybylska D, Nicklas PR, Kiernan AE, White PM. Increased central auditory gain in 5xFAD Alzheimer's disease mice as an early biomarker candidate for Alzheimer's disease diagnosis. Front Neurosci 2023; 17:1106570. [PMID: 37304021 PMCID: PMC10250613 DOI: 10.3389/fnins.2023.1106570] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Accepted: 04/13/2023] [Indexed: 06/13/2023] Open
Abstract
Alzheimer's Disease (AD) is a neurodegenerative illness without a cure. All current therapies require an accurate diagnosis and staging of AD to ensure appropriate care. Central auditory processing disorders (CAPDs) and hearing loss have been associated with AD, and may precede the onset of Alzheimer's dementia. Therefore, CAPD is a possible biomarker candidate for AD diagnosis. However, little is known about how CAPD and AD pathological changes are correlated. In the present study, we investigated auditory changes in AD using transgenic amyloidosis mouse models. AD mouse models were bred to a mouse strain commonly used for auditory experiments, to compensate for the recessive accelerated hearing loss on the parent background. Auditory brainstem response (ABR) recordings revealed significant hearing loss, a reduced ABR wave I amplitude, and increased central gain in 5xFAD mice. In comparison, these effects were milder or reversed in APP/PS1 mice. Longitudinal analyses revealed that in 5xFAD mice, central gain increase preceded ABR wave I amplitude reduction and hearing loss, suggesting that it may originate from lesions in the central nervous system rather than the peripheral loss. Pharmacologically facilitating cholinergic signaling with donepezil reversed the central gain in 5xFAD mice. After the central gain increased, aging 5xFAD mice developed deficits for hearing sound pips in the presence of noise, consistent with CAPD-like symptoms of AD patients. Histological analysis revealed that amyloid plaques were deposited in the auditory cortex of both mouse strains. However, in 5xFAD but not APP/PS1 mice, plaque was observed in the upper auditory brainstem, specifically the inferior colliculus (IC) and the medial geniculate body (MGB). This plaque distribution parallels histological findings from human subjects with AD and correlates in age with central gain increase. Overall, we conclude that auditory alterations in amyloidosis mouse models correlate with amyloid deposits in the auditory brainstem and may be reversed initially through enhanced cholinergic signaling. The alteration of ABR recording related to the increase in central gain prior to AD-related hearing disorders suggests that it could potentially be used as an early biomarker of AD diagnosis.
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Affiliation(s)
- Daxiang Na
- Department of Biomedical Genetics, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Jingyuan Zhang
- Department of Neuroscience, Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Holly J. Beaulac
- Department of Neuroscience, Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Dorota Piekna-Przybylska
- Department of Neuroscience, Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Paige R. Nicklas
- Department of Neuroscience, Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
| | - Amy E. Kiernan
- Department of Biomedical Genetics, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
- Department of Ophthalmology, University of Rochester, Rochester, NY, United States
| | - Patricia M. White
- Department of Neuroscience, Ernest J. Del Monte Institute for Neuroscience, University of Rochester School of Medicine and Dentistry, Rochester, NY, United States
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Kitakaze K, Ali H, Kimoto R, Takenouchi Y, Ishimaru H, Yamashita A, Ueda N, Tanaka T, Okamoto Y, Tsuboi K. GDE7 produces cyclic phosphatidic acid in the ER lumen functioning as a lysophospholipid mediator. Commun Biol 2023; 6:524. [PMID: 37193762 PMCID: PMC10188492 DOI: 10.1038/s42003-023-04900-4] [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: 10/10/2022] [Accepted: 05/02/2023] [Indexed: 05/18/2023] Open
Abstract
Cyclic phosphatidic acid (cPA) is a lipid mediator, which regulates adipogenic differentiation and glucose homeostasis by suppressing nuclear peroxisome proliferator-activated receptor γ (PPARγ). Glycerophosphodiesterase 7 (GDE7) is a Ca2+-dependent lysophospholipase D that localizes in the endoplasmic reticulum. Although mouse GDE7 catalyzes cPA production in a cell-free system, it is unknown whether GDE7 generates cPA in living cells. Here, we demonstrate that human GDE7 possesses cPA-producing activity in living cells as well as in a cell-free system. Furthermore, the active site of human GDE7 is directed towards the luminal side of the endoplasmic reticulum. Mutagenesis revealed that amino acid residues F227 and Y238 are important for catalytic activity. GDE7 suppresses the PPARγ pathway in human mammary MCF-7 and mouse preadipocyte 3T3-L1 cells, suggesting that cPA functions as an intracellular lipid mediator. These findings lead to a better understanding of the biological role of GDE7 and its product, cPA.
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Affiliation(s)
- Keisuke Kitakaze
- Department of Pharmacology, Kawasaki Medical School, Kurashiki, Okayama, Japan.
| | - Hanif Ali
- Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Japan
| | - Raiki Kimoto
- Department of Pharmacology, Kawasaki Medical School, Kurashiki, Okayama, Japan
- Nara Medical University, Kashihara, Nara, Japan
| | - Yasuhiro Takenouchi
- Department of Pharmacology, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Hironobu Ishimaru
- Department of Pharmacology, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Atsushi Yamashita
- Laboratory of Biological Chemistry, Faculty of Pharma-Science, Teikyo University, Tokyo, Japan
| | - Natsuo Ueda
- Department of Biochemistry, Kagawa University School of Medicine, Miki, Kagawa, Japan
| | - Tamotsu Tanaka
- Graduate School of Technology, Industrial and Social Sciences, Tokushima University, Tokushima, Japan
| | - Yasuo Okamoto
- Department of Pharmacology, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Kazuhito Tsuboi
- Department of Pharmacology, Kawasaki Medical School, Kurashiki, Okayama, Japan.
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Kitakaze K, Tsuboi K, Tsuda M, Takenouchi Y, Ishimaru H, Okamoto Y. Development of a selective fluorescence-based enzyme assay for glycerophosphodiesterase family members GDE4 and GDE7. J Lipid Res 2021; 62:100141. [PMID: 34673020 PMCID: PMC8591415 DOI: 10.1016/j.jlr.2021.100141] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 10/08/2021] [Accepted: 10/12/2021] [Indexed: 01/02/2023] Open
Abstract
Lysophosphatidic acid (LPA) is a lipid mediator that regulates various processes, including cell migration and cancer progression. Autotaxin (ATX) is a lysophospholipase D-type exoenzyme that produces extracellular LPA. In contrast, glycerophosphodiesterase (GDE) family members GDE4 and GDE7 are intracellular lysophospholipases D that form LPA, depending on Mg2+ and Ca2+, respectively. Since no fluorescent substrate for these GDEs has been reported, in the present study, we examined whether a fluorescent ATX substrate, FS-3, could be applied to study GDE activity. We found that the membrane fractions of human GDE4- and GDE7-overexpressing human embryonic kidney 293T cells hydrolyzed FS-3 in a manner almost exclusively dependent on Mg2+ and Ca2+, respectively. Using these assay systems, we found that several ATX inhibitors, including α-bromomethylene phosphonate analog of LPA and 3-carbacyclic phosphatidic acid, also potently inhibited GDE4 and GDE7 activities. In contrast, the ATX inhibitor S32826 hardly inhibited these activities. Furthermore, FS-3 was hydrolyzed in a Mg2+-dependent manner by the membrane fraction of human prostate cancer LNCaP cells that express GDE4 endogenously but not by those of GDE4-deficient LNCaP cells. Similar Ca2+-dependent GDE7 activity was observed in human breast cancer MCF-7 cells but not in GDE7-deficient MCF-7 cells. Finally, our assay system could selectively measure GDE4 and GDE7 activities in a mixture of the membrane fractions of GDE4- and GDE7-overexpressing human embryonic kidney 293T cells in the presence of S32826. These findings allow high-throughput assays of GDE4 and GDE7 activities, which could lead to the development of selective inhibitors and stimulators as well as a better understanding of the biological roles of these enzymes.
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Affiliation(s)
- Keisuke Kitakaze
- Department of Pharmacology, Kawasaki Medical School, Kurashiki, Okayama, Japan.
| | - Kazuhito Tsuboi
- Department of Pharmacology, Kawasaki Medical School, Kurashiki, Okayama, Japan.
| | - Maho Tsuda
- Department of Pharmacology, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Yasuhiro Takenouchi
- Department of Pharmacology, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Hironobu Ishimaru
- Department of Pharmacology, Kawasaki Medical School, Kurashiki, Okayama, Japan
| | - Yasuo Okamoto
- Department of Pharmacology, Kawasaki Medical School, Kurashiki, Okayama, Japan
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Role of Lysophospholipid Metabolism in Chronic Myelogenous Leukemia Stem Cells. Cancers (Basel) 2021; 13:cancers13143434. [PMID: 34298649 PMCID: PMC8305981 DOI: 10.3390/cancers13143434] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2021] [Revised: 07/05/2021] [Accepted: 07/07/2021] [Indexed: 02/02/2023] Open
Abstract
Simple Summary In this review, I discuss our recent finding that lysophospholipid metabolism is essential for the maintenance of chronic myelogenous leukemia (CML) stem cells. Lysophospholipids have only one fatty acid chain and so are more hydrophilic than phospholipids, allowing them to act as lipid second messengers. We demonstrated that the stem cell quiescence and TKI resistance displayed by CML stem cells in vivo are sustained by the Gdpd3 enzyme involved in lysophospholipid metabolism. At the mechanistic level, Gdpd3 function allows lysophospholipid metabolism to suppress the AKT/mTORC1-mediated cell growth pathway while activating the stemness factors FOXO and β-catenin. Our results thus link lysophospholipid metabolism to CML stemness, and may thereby open up new therapeutic avenues to overcome CML relapse post-TKI therapy. Abstract It is well known that mature chronic myelogenous leukemia (CML) cells proliferate in response to oncogenic BCR–ABL1-dependent signaling, but how CML stem cells are able to survive in an oncogene-independent manner and cause disease relapse has long been elusive. Here, I put into the context of the broader literature our recent finding that lysophospholipid metabolism is essential for the maintenance of CML stem cells. I describe the fundamentals of lysophospholipid metabolism and discuss how one of its key enzymes, Glycerophosphodiester Phosphodiesterase Domain Containing 3 (Gdpd3), is responsible for maintaining the unique characteristics of CML stem cells. I also explore how this knowledge may be exploited to devise novel therapies for CML patients.
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