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Kofuji S, Wolfe K, Sumita K, Kageyama S, Yoshino H, Hirota Y, Ogawa-Iio A, Kanoh H, Sasaki M, Kofuji K, Davis MI, Pragani R, Shen M, Boxer MB, Nakatsu F, Nigorikawa K, Sasaki T, Takeuchi K, Senda T, Kim SM, Edinger AL, Simeonov A, Sasaki AT. A high dose KRP203 induces cytoplasmic vacuoles associated with altered phosphoinositide segregation and endosome expansion. Biochem Biophys Res Commun 2024; 718:149981. [PMID: 38735134 DOI: 10.1016/j.bbrc.2024.149981] [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: 04/09/2024] [Accepted: 04/22/2024] [Indexed: 05/14/2024]
Abstract
In animal cells, vacuoles are absent, but can be induced by diseases and drugs. While phosphoinositides are critical for membrane trafficking, their role in the formation of these vacuoles remains unclear. The immunosuppressive KRP203/Mocravimod, which antagonizes sphingosine-1-phosphate receptors, has been identified as having novel multimodal activity against phosphoinositide kinases. However, the impact of this novel KRP203 activity is unknown. Here, we show that KRP203 disrupts the spatial organization of phosphoinositides and induces extensive vacuolization in tumor cells and immortalized fibroblasts. The KRP203-induced vacuoles are primarily from endosomes, and augmented by inhibition of PIKFYVE and VPS34. Conversely, overexpression of PTEN decreased KRP203-induced vacuole formation. Furthermore, V-ATPase inhibition completely blunted KRP203-induced vacuolization, pointing to a critical requirement of the endosomal maturation process. Importantly, nearly a half of KRP203-induced vacuoles are significantly decorated with PI4P, a phosphoinositide typically enriched at the plasma membrane and Golgi. These results suggest a model that noncanonical spatial reorganization of phosphoinositides by KRP203 alters the endosomal maturation process, leading to vacuolization. Taken together, this study reveals a previously unrecognized bioactivity of KRP203 as a vacuole-inducing agent and its unique mechanism of phosphoinositide modulation, providing a new insight of phosphoinositide regulation into vacuolization-associated diseases and their molecular pathologies.
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Affiliation(s)
- Satoshi Kofuji
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Department of Developmental and Regenerative Biology, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, 113-8510, Japan
| | - Kara Wolfe
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Kazutaka Sumita
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Department of Endovascular Surgery, Tokyo Medical and Dental University, Tokyo, 113-8510, Japan
| | - Shun Kageyama
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0052, Japan
| | - Hirofumi Yoshino
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Yoshihisa Hirota
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Department of Bioscience and Engineering, College of Systems Engineering and Science, Shibaura Institute of Technology, Minuma-ku, Saitama, 337-8570, Japan
| | - Aki Ogawa-Iio
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Department of Bioscience and Engineering, College of Systems Engineering and Science, Shibaura Institute of Technology, Minuma-ku, Saitama, 337-8570, Japan
| | - Hirotaka Kanoh
- Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0052, Japan
| | - Mika Sasaki
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Kaori Kofuji
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA
| | - Mindy I Davis
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Rajan Pragani
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Min Shen
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Matthew B Boxer
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Fubito Nakatsu
- Department of Neurochemistry and Molecular Cell Biology, Niigata University School of Medicine and Graduate School of Medical/Dental Sciences, Niigata, Japan
| | - Kiyomi Nigorikawa
- Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan
| | - Takehiko Sasaki
- Department of Biochemical Pathophysiology, Tokyo Medical and Dental University, Tokyo, 113-8510, Japan
| | - Koh Takeuchi
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Toshiya Senda
- Structural Biology Research Center, High Energy Accelerator Research Organization (KEK), Tsukuba, Ibaraki, 305-0801, Japan; Department of Accelerator Science, SOKENDAI, Japan; Faculty of Pure and Applied Sciences, University of Tsukuba, Ibaraki, 305-8572, Japan
| | - Seong M Kim
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California Irvine, California, 92697, USA
| | - Aimee L Edinger
- Department of Developmental and Cell Biology, School of Biological Sciences, University of California Irvine, California, 92697, USA
| | - Anton Simeonov
- National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD, 20850, USA
| | - Atsuo T Sasaki
- Division of Hematology and Oncology, Department of Internal Medicine, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata, 997-0052, Japan; Department of Cancer Biology, University of Cincinnati College of Medicine, Cincinnati, OH, 45267, USA; Department of Neurosurgery, Brain Tumor Center at UC Gardner Neuroscience Institute, Cincinnati, OH, 45267, USA; Department of Clinical and Molecular Genetics, Hiroshima University Hospital, Hiroshima, 734-8551, Japan.
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Tahoun M, Sadaka AS. Deregulated expression of autophagy genes; PIK3C3 and RAB7A in COVID-19 patients. Hum Immunol 2024; 85:110801. [PMID: 38609772 DOI: 10.1016/j.humimm.2024.110801] [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: 01/05/2024] [Revised: 03/20/2024] [Accepted: 04/08/2024] [Indexed: 04/14/2024]
Abstract
BACKGROUND The role of autophagy in coronaviruses infection and replication has a lot of debate. Autophagy involves the catalytic breakdown of intracellular components to be subsequently recycled by the lysosome. The aim of the study was to evaluate autophagy genes; PIK3C3 and RAB7A expressions in COVID-19 patients, and identify if PIK3C3 and RAB7A can be used as markers for monitoring COVID-19 patients. METHODS A case-control study was carried out on 50 patients and 50 healthy controls. Genes expression was performed using quantitative real-time polymerase chain reaction. RESULTS Compared to controls, PIK3C3 and RAB7A gene expression levels were significantly lower in patients (p < 0.001) with approximately with 9.4 and 2.3 decreased fold in PIK3C3 and RAB7A respectively. The ROC curve of PIK3C3 and RAB7A expressions showed sensitivity of 84 % and 74 % and specificity of 98 % and 78 % respectively. There was a positive correlation between PIK3C3 expression and WBCs, absolute neutrophil count, interleukin-6, D-dimer, and ALT among patients and between RAB7A expression and WBCs, CRP, IL-6, D-dimer and ALT in patients. CONCLUSIONS The study showed reduction of PIK3C3 and RAB7A expressions in COVID-19 patients. However, further studies are recommended to clarify their roles in the disease pathogenies as autophagy genes.
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Affiliation(s)
- Mona Tahoun
- Clinical and Chemical Pathology Department, Faculty of Medicine, Alexandria University, Egypt.
| | - Ahmed S Sadaka
- Chest Diseases Department, Faculty of Medicine, Alexandria University, Egypt
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3
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Wang K, Kong F, Qiu Y, Chen T, Fu J, Jin X, Su Y, Gu Y, Hu Z, Li J. Autophagy regulation and protein kinase activity of PIK3C3 controls sertoli cell polarity through its negative regulation on SCIN (scinderin). Autophagy 2023; 19:2934-2957. [PMID: 37450577 PMCID: PMC10549198 DOI: 10.1080/15548627.2023.2235195] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Revised: 06/25/2023] [Accepted: 07/06/2023] [Indexed: 07/18/2023] Open
Abstract
Sertoli cells are highly polarized testicular cells that provide a nurturing environment for germ cell development and maturation during spermatogenesis. The class III phosphatidylinositol 3-kinase (PtdIns3K) plays core roles in macroautophagy in various cell types; however, its role in Sertoli cells remains unclear. Here, we generated a mouse line in which the gene encoding the catalytic subunit, Pik3c3, was specifically deleted in Sertoli cells (cKO) and found that after one round of normal spermatogenesis, the cKO mice quickly became infertile and showed disruption of Sertoli cell polarity and impaired spermiogenesis. Subsequent proteomics and phosphoproteomics analyses enriched the F-actin cytoskeleton network involved in the disorganized Sertoli-cell structure in cKO testis which we identified a significant increase of the F-actin negative regulator SCIN (scinderin) and the reduced phosphorylation of HDAC6, an α-tubulin deacetylase. Our results further demonstrated that the accumulation of SCIN in cKO Sertoli cells caused the disorder and disassembly of the F-actin cytoskeleton, which was related to the failure of SCIN degradation through the autophagy-lysosome pathway. Additionally, we found that the phosphorylation of HDAC6 at site S59 by PIK3C3 was essential for its degradation through the ubiquitin-proteasome pathway. As a result, the HDAC6 that accumulated in cKO Sertoli cells deacetylated SCIN at site K189 and led to a disorganized F-actin cytoskeleton. Taken together, our findings elucidate a new mechanism for PIK3C3 in maintaining the polarity of Sertoli cells, in which both its autophagy regulation or protein kinase activities are required for the stabilization of the actin cytoskeleton.Abbreviations: ACTB: actin, beta; AR: androgen receptor; ATG14: autophagy related 14; BafA1: bafilomycin A1; BECN1: beclin 1, autophagy related; BTB: blood-testis barrier; CASP3: caspase 3; CDC42: cell division cycle 42; CDH2: cadherin 2; CHX: cycloheximide; CTNNA1: catenin (cadherin associated protein), alpha 1; CYP11A1: cytochrome P450, family 11, subfamily A, polypeptide 1; EBSS: Earle's balanced salt solution; ES: ectoplasmic specialization; FITC: fluorescein isothiocyanate; GAPDH: glyceraldehyde-3-phosphate dehydrogenase; GCNA: germ cell nuclear acidic protein; GJA1: gap junction protein, alpha 1; H2AX: H2A.X variant histone; HDAC6: histone deacetylase 6; KIT: KIT proto-oncogene, receptor tyrosine kinase; LAMP1: lysosomal associated membrane protein 1; MAP3K5: mitogen-activated protein kinase kinase kinase 5; MAP1LC3B: microtubule associated protein 1 light chain 3 beta; OCLN: occludin; PIK3C3: phosphatidylinositol 3-kinase catalytic subunit type 3; PIK3R4: phosphoinositide-3-kinase regulatory subunit 4; PNA: arachis hypogaea lectin; RAC1: Rac family small GTPase 1; SCIN: scinderin; SQSTM1/p62: sequestosome 1; SSC: spermatogonia stem cell; STK11: serine/threonine kinase 11; TJP1: tight junction protein 1; TubA: tubastatin A; TUBB3: tubulin beta 3 class III; TUNEL: TdT-mediated dUTP nick-end labeling; UB: ubiquitin; UVRAG: UV radiation resistance associated gene; VIM: vimentin; WT1: WT1 transcription factor; ZBTB16: zinc finger and BTB domain containing 16.
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Affiliation(s)
- Kehan Wang
- State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Feifei Kong
- Assisted Reproduction Unit, Department of Obstetrics and Gynecology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang, China
| | - Yuexin Qiu
- State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Tao Chen
- State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jiayi Fu
- State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Xin Jin
- Department of Center of Reproductive Medicine, Wuxi Maternity and Child Health Care Hospital, Nanjing Medical University, Wuxi, Jiangsu, China
| | - Youqiang Su
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, China
| | - Yayun Gu
- State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Zhibin Hu
- State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu, China
- Department of Epidemiology and Biostatistics, International Joint Research Center on Environment and Human Health, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, China
| | - Jing Li
- State Key Laboratory of Reproductive Medicine and Offspring Health, Nanjing Medical University, Nanjing, Jiangsu, China
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Hu Z, Luo Y, Liu Y, Luo Y, Wang L, Gou S, Peng Y, Wei R, Jia D, Wang Y, Gao S, Zhang Y. Partial inhibition of class III PI3K VPS-34 ameliorates motor aging and prolongs health span. PLoS Biol 2023; 21:e3002165. [PMID: 37432924 DOI: 10.1371/journal.pbio.3002165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 05/13/2023] [Indexed: 07/13/2023] Open
Abstract
Global increase of life expectancy is rarely accompanied by increased health span, calling for a greater understanding of age-associated behavioral decline. Motor independence is strongly associated with the quality of life of elderly people, yet the regulators for motor aging have not been systematically explored. Here, we designed a fast and efficient genome-wide screening assay in Caenorhabditis elegans and identified 34 consistent genes as potential regulators of motor aging. Among the top hits, we found VPS-34, the class III phosphatidylinositol 3-kinase that phosphorylates phosphatidylinositol (PI) to phosphatidylinositol 3-phosphate (PI(3)P), regulates motor function in aged but not young worms. It primarily functions in aged motor neurons by inhibiting PI(3)P-PI-PI(4)P conversion to reduce neurotransmission at the neuromuscular junction (NMJ). Genetic and pharmacological inhibition of VPS-34 improve neurotransmission and muscle integrity, ameliorating motor aging in both worms and mice. Thus, our genome-wide screening revealed an evolutionarily conserved, actionable target to delay motor aging and prolong health span.
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Affiliation(s)
- Zhongliang Hu
- National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yamei Luo
- National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Yuting Liu
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Yaru Luo
- National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Liangce Wang
- National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Shengsong Gou
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Pediatrics, State Key Laboratory of Biotherapy, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Yuling Peng
- National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Rui Wei
- National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Da Jia
- Key Laboratory of Birth Defects and Related Diseases of Women and Children, Department of Pediatrics, State Key Laboratory of Biotherapy, West China Second University Hospital, Sichuan University, Chengdu, China
| | - Yuan Wang
- National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
| | - Shangbang Gao
- Key Laboratory of Molecular Biophysics of the Ministry of Education, College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan, China
| | - Yan Zhang
- National Clinical Research Center for Geriatrics, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan, China
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5
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Liu Y, Yang Q, Chen S, Li Z, Fu L. Targeting VPS34 in autophagy: An update on pharmacological small-molecule compounds. Eur J Med Chem 2023; 256:115467. [PMID: 37178482 DOI: 10.1016/j.ejmech.2023.115467] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 04/19/2023] [Accepted: 05/05/2023] [Indexed: 05/15/2023]
Abstract
VPS34 is well-known to be the unique member of the class III phosphoinositide 3-kinase (PI3K) family, forming VPS34 complex 1 and complex 2, which are involved in several key physiological processes. Of note, VPS34 complex 1 is an important node of autophagosome generation, which controls T cell metabolism and maintains cellular homeostasis through the autophagic pathway. And, VPS34 complex 2 is involved in endocytosis as well as vesicular transport, and is closely related to neurotransmission, antigen presentation and brain development. Due to the two important biological functions of VPS34, its dysregulation can lead to the development of cardiovascular disease, cancer, neurological disorders, and many types of human diseases by altering normal human physiology. Thus, in this review, we not only summarize the molecular structure and function of VPS34, but demonstrate the relationships between VPS34 and human diseases. Moreover, we further discuss the current small molecule inhibitors targeting VPS34 based upon the structure and function of VPS34, which may provide an insight into the future targeted drug development.
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Affiliation(s)
- Yuan Liu
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
| | - Qilin Yang
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
| | - Siwei Chen
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
| | - Zixiang Li
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China
| | - Leilei Fu
- Sichuan Engineering Research Center for Biomimetic Synthesis of Natural Drugs, School of Life Science and Engineering, Southwest Jiaotong University, Chengdu, 610031, China.
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6
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Targeting Class I-II-III PI3Ks in Cancer Therapy: Recent Advances in Tumor Biology and Preclinical Research. Cancers (Basel) 2023; 15:cancers15030784. [PMID: 36765741 PMCID: PMC9913247 DOI: 10.3390/cancers15030784] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Revised: 01/15/2023] [Accepted: 01/17/2023] [Indexed: 02/01/2023] Open
Abstract
Phosphatidylinositol-3-kinase (PI3K) enzymes, producing signaling phosphoinositides at plasma and intracellular membranes, are key in intracellular signaling and vesicular trafficking pathways. PI3K is a family of eight enzymes divided into three classes with various functions in physiology and largely deregulated in cancer. Here, we will review the recent evidence obtained during the last 5 years on the roles of PI3K class I, II and III isoforms in tumor biology and on the anti-tumoral action of PI3K inhibitors in preclinical cancer models. The dependency of tumors to PI3K isoforms is dictated by both genetics and context (e.g., the microenvironment). The understanding of class II/III isoforms in cancer development and progression remains scarce. Nonetheless, the limited available data are consistent and reveal that there is an interdependency between the pathways controlled by all PI3K class members in their role to promote cancer cell proliferation, survival, growth, migration and metabolism. It is unknown whether this feature contributes to partial treatment failure with isoform-selective PI3K inhibitors. Hence, a better understanding of class II/III functions to efficiently inhibit their positive and negative interactions with class I PI3Ks is needed. This research will provide the proof-of-concept to develop combination treatment strategies targeting several PI3K isoforms simultaneously.
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7
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Li H, Zhang L, Zhang L, Han R. Autophagy in striated muscle diseases. Front Cardiovasc Med 2022; 9:1000067. [PMID: 36312227 PMCID: PMC9606591 DOI: 10.3389/fcvm.2022.1000067] [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: 07/21/2022] [Accepted: 09/27/2022] [Indexed: 11/13/2022] Open
Abstract
Impaired biomolecules and cellular organelles are gradually built up during the development and aging of organisms, and this deteriorating process is expedited under stress conditions. As a major lysosome-mediated catabolic process, autophagy has evolved to eradicate these damaged cellular components and recycle nutrients to restore cellular homeostasis and fitness. The autophagic activities are altered under various disease conditions such as ischemia-reperfusion cardiac injury, sarcopenia, and genetic myopathies, which impact multiple cellular processes related to cellular growth and survival in cardiac and skeletal muscles. Thus, autophagy has been the focus for therapeutic development to treat these muscle diseases. To develop the specific and effective interventions targeting autophagy, it is essential to understand the molecular mechanisms by which autophagy is altered in heart and skeletal muscle disorders. Herein, we summarize how autophagy alterations are linked to cardiac and skeletal muscle defects and how these alterations occur. We further discuss potential pharmacological and genetic interventions to regulate autophagy activities and their applications in cardiac and skeletal muscle diseases.
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Affiliation(s)
- Haiwen Li
- Department of Surgery, Davis Heart and Lung Research Institute, Biomedical Sciences Graduate Program, Biophysics Graduate Program, The Ohio State University Wexner Medical Center, Columbus, OH, United States,*Correspondence: Haiwen Li,
| | - Lingqiang Zhang
- State Key Laboratory of Proteomics, National Center of Protein Sciences (Beijing), Beijing Institute of Lifeomics, Beijing, China
| | - Lei Zhang
- Department of Anatomy and Neurobiology, Shanghai Yangzhi Rehabilitation Hospital, Shanghai Sunshine Rehabilitation Center, School of Medicine, Tongji University, Shanghai, China
| | - Renzhi Han
- Department of Surgery, Davis Heart and Lung Research Institute, Biomedical Sciences Graduate Program, Biophysics Graduate Program, The Ohio State University Wexner Medical Center, Columbus, OH, United States,Renzhi Han,
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8
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Postoak JL, Song W, Yang G, Guo X, Xiao S, Saffold CE, Zhang J, Joyce S, Manley NR, Wu L, Van Kaer L. Thymic epithelial cells require lipid kinase Vps34 for CD4 but not CD8 T cell selection. J Exp Med 2022; 219:e20212554. [PMID: 35997680 PMCID: PMC9402993 DOI: 10.1084/jem.20212554] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 06/22/2022] [Accepted: 08/03/2022] [Indexed: 11/04/2022] Open
Abstract
The generation of a functional, self-tolerant T cell receptor (TCR) repertoire depends on interactions between developing thymocytes and antigen-presenting thymic epithelial cells (TECs). Cortical TECs (cTECs) rely on unique antigen-processing machinery to generate self-peptides specialized for T cell positive selection. In our current study, we focus on the lipid kinase Vps34, which has been implicated in autophagy and endocytic vesicle trafficking. We show that loss of Vps34 in TECs causes profound defects in the positive selection of the CD4 T cell lineage but not the CD8 T cell lineage. Utilizing TCR sequencing, we show that T cell selection in conditional mutants causes altered repertoire properties including reduced clonal sharing. cTECs from mutant mice display an increased abundance of invariant chain intermediates bound to surface MHC class II molecules, indicating altered antigen processing. Collectively, these studies identify lipid kinase Vps34 as an important contributor to the repertoire of selecting ligands processed and presented by TECs to developing CD4 T cells.
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Affiliation(s)
- J. Luke Postoak
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN
| | - Wenqiang Song
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN
| | - Guan Yang
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN
| | - Xingyi Guo
- Department of Biomedical Informatics, Vanderbilt University School of Medicine, Nashville, TN
| | - Shiyun Xiao
- Department of Genetics, University of Georgia, Athens, GA
| | - Cherie E. Saffold
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN
| | - Jianhua Zhang
- Department of Pathology, University of Alabama at Birmingham, Birmingham, AL
- Birmingham Veterans Affairs Medical Center, Birmingham, AL
| | - Sebastian Joyce
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN
- Department of Veterans Affairs, Tennessee Valley Healthcare System, Nashville, TN
| | | | - Lan Wu
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN
| | - Luc Van Kaer
- Department of Pathology, Microbiology and Immunology, Vanderbilt University School of Medicine, Nashville, TN
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9
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Class III PI3K Biology. Curr Top Microbiol Immunol 2022; 436:69-93. [DOI: 10.1007/978-3-031-06566-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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10
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The Role of Phosphatidylinositol 3-Kinase Catalytic Subunit Type 3 in the Pathogenesis of Human Cancer. Int J Mol Sci 2021; 22:ijms222010964. [PMID: 34681622 PMCID: PMC8535862 DOI: 10.3390/ijms222010964] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 10/02/2021] [Accepted: 10/08/2021] [Indexed: 12/12/2022] Open
Abstract
Phosphatidylinositol 3-kinase catalytic subunit type 3 (PIK3C3), the mammalian ortholog of yeast vesicular protein sorting 34 (Vps34), belongs to the phosphoinositide 3-kinase (PI3K) family. PIK3C3 can phosphorylate phosphatidylinositol (PtdIns) to generate phosphatidylinositol 3-phosphate (PI3P), a phospholipid central to autophagy. Inhibition of PIK3C3 successfully inhibits autophagy. Autophagy maintains cell survival when modifications occur in the cellular environment and helps tumor cells resist metabolic stress and cancer treatment. In addition, PIK3C3 could induce oncogenic transformation and enhance tumor cell proliferation, growth, and invasion through mechanisms independent of autophagy. This review addresses the structural and functional features, tissue distribution, and expression pattern of PIK3C3 in a variety of human tumors and highlights the underlying mechanisms involved in carcinogenesis. The implications in cancer biology, patient prognosis prediction, and cancer therapy are discussed. Altogether, the discovery of pharmacological inhibitors of PIK3C3 could reveal novel strategies for improving treatment outcomes for PIK3C3-mediated human diseases.
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11
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Li D, Vogel P, Li-Harms X, Wang B, Kundu M. ATG14 and RB1CC1 play essential roles in maintaining muscle homeostasis. Autophagy 2021; 17:2576-2585. [PMID: 33794726 DOI: 10.1080/15548627.2021.1911549] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Defects in macroautophagy/autophagy are implicated in the pathogenesis of neuromuscular and heart diseases. To precisely define the roles of autophagy-related genes in skeletal and cardiac muscles, we generated muscle-specific rb1cc1- and atg14-conditional knockout (cKO) mice by using Ckm/Ckmm2-Cre and compared their phenotypes to those of ulk1 ulk2-conditional double-knockout (cDKO) mice. atg14-cKO mice developed hypertrophic cardiomyopathy, which was associated with abnormal accumulation of autophagic cargoes in the heart and early mortality. Skeletal muscles of both atg14-cKO and rb1cc1-cKO mice showed features of autophagic vacuolar myopathy with ubiquitin+ SQSTM1+ deposits, but only those of rb1cc1-cKO mice showed TARDBP/TDP-43+ pathology and other features of the inclusion body myopathy-like disease we previously described in ulk1 ulk2-cDKO mice. Herein, we highlight tissue-specific differences between skeletal and cardiac muscles in their reliance on core autophagy proteins and unique roles for ULK1-ULK2 and RB1CC1 among these proteins in the development of TARDBP+ pathology.ABBREVIATIONS:AVM: autophagic vacuolar myopathy; cDKO: conditional double knockout; cKO: conditional knockout; H&E: hematoxylin and eosin; IBM: inclusion body myopathy; mtDNA: mitochondrial DNA; PFA: paraformaldehyde; RNP: ribonucleoprotein; TBST: Tris-buffered saline with 0.2% Triton X-100.
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Affiliation(s)
- Dongfang Li
- Departments of Pathology, St. Jude Children's Research Hospital, Memphis, TN, USA.,Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Peter Vogel
- Departments of Pathology, St. Jude Children's Research Hospital, Memphis, TN, USA.,Veterinary Pathology Core, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Xiujie Li-Harms
- Departments of Pathology, St. Jude Children's Research Hospital, Memphis, TN, USA.,Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
| | - Bo Wang
- Departments of Pathology, St. Jude Children's Research Hospital, Memphis, TN, USA.,Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN, USA.,State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian Province, Fujian Province, China
| | - Mondira Kundu
- Departments of Pathology, St. Jude Children's Research Hospital, Memphis, TN, USA.,Cell and Molecular Biology, St. Jude Children's Research Hospital, Memphis, TN, USA
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12
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Loss of Class III Phosphoinositide 3-Kinase Vps34 Results in Cone Degeneration. BIOLOGY 2020; 9:biology9110384. [PMID: 33171845 PMCID: PMC7695136 DOI: 10.3390/biology9110384] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Revised: 10/26/2020] [Accepted: 11/04/2020] [Indexed: 12/15/2022]
Abstract
The major pathway for the production of the low-abundance membrane lipid phosphatidylinositol 3-phosphate (PI(3)P) synthesis is catalyzed by class III phosphoinositide 3-kinase (PI3K) Vps34. The absence of Vps34 was previously found to disrupt autophagy and other membrane-trafficking pathways in some sensory neurons, but the roles of phosphatidylinositol 3-phosphate and Vps34 in cone photoreceptor cells have not previously been explored. We found that the deletion of Vps34 in neighboring rods in mouse retina did not disrupt cone function up to 8 weeks after birth, despite diminished rod function. Immunoblotting and lipid analysis of cones isolated from the cone-dominant retinas of the neural retina leucine zipper gene knockout mice revealed that both PI(3)P and Vps34 protein are present in mouse cones. To determine whether Vps34 and PI(3)P are important for cone function, we conditionally deleted Vps34 in cone photoreceptor cells of the mouse retina. Overall retinal morphology and rod function appeared to be unaffected. However, the loss of Vps34 in cones resulted in the loss of structure and function. There was a substantial reduction throughout the retina in the number of cones staining for M-opsin, S-opsin, cone arrestin, and peanut agglutinin, revealing degeneration of cones. These studies indicate that class III PI3K, and presumably PI(3)P, play essential roles in cone photoreceptor cell function and survival.
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13
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Brennan S, Garcia-Castañeda M, Michelucci A, Sabha N, Malik S, Groom L, Wei LaPierre L, Dowling JJ, Dirksen RT. Mouse model of severe recessive RYR1-related myopathy. Hum Mol Genet 2020; 28:3024-3036. [PMID: 31107960 DOI: 10.1093/hmg/ddz105] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 05/07/2019] [Accepted: 05/13/2019] [Indexed: 12/16/2022] Open
Abstract
Ryanodine receptor type I (RYR1)-related myopathies (RYR1 RM) are a clinically and histopathologically heterogeneous group of conditions that represent the most common subtype of childhood onset non-dystrophic muscle disorders. There are no treatments for this severe group of diseases. A major barrier to therapy development is the lack of an animal model that mirrors the clinical severity of pediatric cases of the disease. To address this, we used CRISPR/Cas9 gene editing to generate a novel recessive mouse model of RYR1 RM. This mouse (Ryr1TM/Indel) possesses a patient-relevant point mutation (T4706M) engineered into 1 allele and a 16 base pair frameshift deletion engineered into the second allele. Ryr1TM/Indel mice exhibit an overt phenotype beginning at 14 days of age that consists of reduced body/muscle mass and myofibre hypotrophy. Ryr1TM/Indel mice become progressively inactive from that point onward and die at a median age of 42 days. Histopathological assessment shows myofibre hypotrophy, increased central nuclei and decreased triad number but no clear evidence of metabolic cores. Biochemical analysis reveals a marked decrease in RYR1 protein levels (20% of normal) as compared to only a 50% decrease in transcript. Functional studies at end stage show significantly reduced electrically evoked Ca2+ release and force production. In summary, Ryr1TM/Indel mice exhibit a post-natal lethal recessive form of RYR1 RM that pheno-copies the severe congenital clinical presentation seen in a subgroup of RYR1 RM children. Thus, Ryr1TM/Indel mice represent a powerful model for both establishing the pathomechanisms of recessive RYR1 RM and pre-clinical testing of therapies for efficacy.
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Affiliation(s)
- Stephanie Brennan
- Program for Genetics and Genome Biology, Hospital for Sick Children, 686 Bay St, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, 686 Bay St, Toronto, Ontario, M5G 0A4, Canada
| | - Maricela Garcia-Castañeda
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642 USA
| | - Antonio Michelucci
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642 USA
| | - Nesrin Sabha
- Program for Genetics and Genome Biology, Hospital for Sick Children, 686 Bay St, Toronto, Ontario, M5G 0A4, Canada
| | - Sundeep Malik
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642 USA
| | - Linda Groom
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642 USA
| | - Lan Wei LaPierre
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642 USA
| | - James J Dowling
- Program for Genetics and Genome Biology, Hospital for Sick Children, 686 Bay St, Toronto, Ontario, M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, 686 Bay St, Toronto, Ontario, M5G 0A4, Canada.,Division of Neurology, Hospital for Sick Children, 686 Bay St, Toronto, Ontario, M5G 0A4, Canada
| | - Robert T Dirksen
- Department of Pharmacology and Physiology, University of Rochester, 601 Elmwood Avenue, Rochester, NY 14642 USA
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14
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He F, Nichols RM, Kailasam L, Wensel TG, Agosto MA. Critical Role for Phosphatidylinositol-3 Kinase Vps34/PIK3C3 in ON-Bipolar Cells. Invest Ophthalmol Vis Sci 2019; 60:2861-2874. [PMID: 31260037 PMCID: PMC6607926 DOI: 10.1167/iovs.19-26586] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Purpose Phosphatidylinositol-3-phosphate (PI(3)P), and Vps34, the type III phosphatidylinositol 3-kinase primarily responsible for its production, are important for function and survival of sensory neurons, where they have key roles in membrane processing events, such as autophagy, endosome processing, and fusion of membranes bearing ubiquitinated cargos with lysosomes. We examined their roles in the most abundant class of secondary neurons in the vertebrate retina, the ON-bipolar cells (ON-BCs). Methods A conditional Vps34 knockout mouse line was generated by crossing Vps34 floxed mice with transgenic mice expressing Cre recombinase in ON-BCs. Structural changes in the retina were determined by immunofluorescence and electron microscopy, and bipolar cell function was determined by electroretinography. Results Vps34 deletion led to selective death of ON-BCs, a thinning of the inner nuclear layer, and a progressive decline of electroretinogram b-wave amplitudes. There was no evidence for loss of other retinal neurons, or disruption of rod-horizontal cell contacts in the outer plexiform layer. Loss of Vps34 led to aberrant accumulation of membranes positive for autophagy markers LC3, p62, and ubiquitin, accumulation of endosomal membranes positive for Rab7, and accumulation of lysosomes. Similar effects were observed in Purkinje cells of the cerebellum, leading to severe and progressive ataxia. Conclusions These results support an essential role for PI(3)P in fusion of autophagosomes with lysosomes and in late endosome maturation. The cell death resulting from Vps34 knockout suggests that these processes are essential for the health of ON-BCs.
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Affiliation(s)
- Feng He
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States
| | - Ralph M Nichols
- Department of Ophthalmology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States
| | - Lavanya Kailasam
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States
| | - Theodore G Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States.,Department of Ophthalmology, Baylor College of Medicine, One Baylor Plaza, Houston, Texas, United States
| | - Melina A Agosto
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas, United States
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15
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Palamiuc L, Ravi A, Emerling BM. Phosphoinositides in autophagy: current roles and future insights. FEBS J 2019; 287:222-238. [DOI: 10.1111/febs.15127] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 08/27/2019] [Accepted: 11/05/2019] [Indexed: 12/22/2022]
Affiliation(s)
- Lavinia Palamiuc
- Sanford Burnham Prebys Medical Discovery Institute Cancer Metabolism and Signaling Networks Program La JollaCA USA
| | - Archna Ravi
- Sanford Burnham Prebys Medical Discovery Institute Cancer Metabolism and Signaling Networks Program La JollaCA USA
| | - Brooke M. Emerling
- Sanford Burnham Prebys Medical Discovery Institute Cancer Metabolism and Signaling Networks Program La JollaCA USA
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16
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Volpatti JR, Al-Maawali A, Smith L, Al-Hashim A, Brill JA, Dowling JJ. The expanding spectrum of neurological disorders of phosphoinositide metabolism. Dis Model Mech 2019; 12:12/8/dmm038174. [PMID: 31413155 PMCID: PMC6737944 DOI: 10.1242/dmm.038174] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Phosphoinositides (PIPs) are a ubiquitous group of seven low-abundance phospholipids that play a crucial role in defining localized membrane properties and that regulate myriad cellular processes, including cytoskeletal remodeling, cell signaling cascades, ion channel activity and membrane traffic. PIP homeostasis is tightly regulated by numerous inositol kinases and phosphatases, which phosphorylate and dephosphorylate distinct PIP species. The importance of these phospholipids, and of the enzymes that regulate them, is increasingly being recognized, with the identification of human neurological disorders that are caused by mutations in PIP-modulating enzymes. Genetic disorders of PIP metabolism include forms of epilepsy, neurodegenerative disease, brain malformation syndromes, peripheral neuropathy and congenital myopathy. In this Review, we provide an overview of PIP function and regulation, delineate the disorders associated with mutations in genes that modulate or utilize PIPs, and discuss what is understood about gene function and disease pathogenesis as established through animal models of these diseases. Summary: This Review highlights the intersection between phosphoinositides and the enzymes that regulate their metabolism, which together are crucial regulators of myriad cellular processes and neurological disorders.
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Affiliation(s)
- Jonathan R Volpatti
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Almundher Al-Maawali
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Genetics, College of Medicine and Health Sciences, Sultan Qaboos University, Muscat 123, Oman
| | - Lindsay Smith
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Aqeela Al-Hashim
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada.,Department of Neuroscience, King Fahad Medical City, Riyadh 11525, Saudi Arabia
| | - Julie A Brill
- Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada.,Program in Cell Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada
| | - James J Dowling
- Division of Neurology and Program in Genetics and Genome Biology, The Hospital for Sick Children, Toronto, ON M5G 0A4, Canada .,Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
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17
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Tasfaout H, Cowling BS, Laporte J. Centronuclear myopathies under attack: A plethora of therapeutic targets. J Neuromuscul Dis 2019; 5:387-406. [PMID: 30103348 PMCID: PMC6218136 DOI: 10.3233/jnd-180309] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Centronuclear myopathies are a group of congenital myopathies characterized by severe muscle weakness, genetic heterogeneity, and defects in the structural organization of muscle fibers. Their names are derived from the central position of nuclei on biopsies, while they are at the fiber periphery under normal conditions. No specific therapy exists yet for these debilitating diseases. Mutations in the myotubularin phosphoinositides phosphatase, the GTPase dynamin 2, or amphiphysin 2 have been identified to cause respectively X-linked centronuclear myopathies (also called myotubular myopathy) or autosomal dominant and recessive forms. Mutations in additional genes, as RYR1, TTN, SPEG or CACNA1S, were linked to phenotypes that can overlap with centronuclear myopathies. Numerous animal models of centronuclear myopathies have been studied over the last 15 years, ranging from invertebrate to large mammalian models. Their characterization led to a partial understanding of the pathomechanisms of these diseases and allowed the recent validation of therapeutic proof-of-concepts. Here, we review the different therapeutic strategies that have been tested so far for centronuclear myopathies, some of which may be translated to patients.
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Affiliation(s)
- Hichem Tasfaout
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Belinda S. Cowling
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
| | - Jocelyn Laporte
- Department of Translational Medicine and Neurogenetics, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Illkirch, France
- Institut National de la Santé et de la Recherche Médicale (INSERM), U1258, Illkirch, France
- Centre National de la Recherche Scientifique (CNRS), UMR7104, Illkirch, France
- Université de Strasbourg, Illkirch, France
- Correspondence to: Jocelyn Laporte, Tel.: 33 0 388653412; E-mail:
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18
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Vps34/PI3KC3 deletion in kidney proximal tubules impairs apical trafficking and blocks autophagic flux, causing a Fanconi-like syndrome and renal insufficiency. Sci Rep 2018; 8:14133. [PMID: 30237523 PMCID: PMC6148293 DOI: 10.1038/s41598-018-32389-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 07/01/2018] [Indexed: 12/21/2022] Open
Abstract
Kidney proximal tubular cells (PTCs) are highly specialized for ultrafiltrate reabsorption and serve as paradigm of apical epithelial differentiation. Vps34/PI3-kinase type III (PI3KC3) regulates endosomal dynamics, macroautophagy and lysosomal function. However, its in vivo role in PTCs has not been evaluated. Conditional deletion of Vps34/PI3KC3 in PTCs by Pax8-Cre resulted in early (P7) PTC dysfunction, manifested by Fanconi-like syndrome, followed by kidney failure (P14) and death. By confocal microscopy, Vps34∆/∆ PTCs showed preserved apico-basal specification (brush border, NHERF-1 versus Na+/K+-ATPase, ankyrin-G) but basal redistribution of late-endosomes/lysosomes (LAMP-1) and mis-localization to lysosomes of apical recycling endocytic receptors (megalin, cubilin) and apical non-recycling solute carriers (NaPi-IIa, SGLT-2). Defective endocytosis was confirmed by Texas-red-ovalbumin tracing and reduced albumin content. Disruption of Rab-11 and perinuclear galectin-3 compartments suggested mechanistic clues for defective receptor recycling and apical biosynthetic trafficking. p62-dependent autophagy was triggered yet abortive (p62 co-localization with LC3 but not LAMP-1) and PTCs became vacuolated. Impaired lysosomal positioning and blocked autophagy are known causes of cell stress. Thus, early trafficking defects show that Vps34 is a key in vivo component of molecular machineries governing apical vesicular trafficking, thus absorptive function in PTCs. Functional defects underline the essential role of Vps34 for PTC homeostasis and kidney survival.
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19
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Deficiency in class III PI3-kinase confers postnatal lethality with IBD-like features in zebrafish. Nat Commun 2018; 9:2639. [PMID: 29980668 PMCID: PMC6035235 DOI: 10.1038/s41467-018-05105-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 05/22/2018] [Indexed: 12/26/2022] Open
Abstract
The class III PI3-kinase (PIK3C3) is an enzyme responsible for the generation of phosphatidylinositol 3-phosphate (PI3P), a critical component of vesicular membrane. Here, we report that PIK3C3 deficiency in zebrafish results in intestinal injury and inflammation. In pik3c3 mutants, gut tube forms but fails to be maintained. Gene expression analysis reveals that barrier-function-related inflammatory bowel disease (IBD) susceptibility genes (e-cadherin, hnf4a, ttc7a) are suppressed, while inflammatory response genes are stimulated in the mutants. Histological analysis shows neutrophil infiltration into mutant intestinal epithelium and the clearance of gut microbiota. Yet, gut microorganisms appear dispensable as mutants cultured under germ-free condition have similar intestinal defects. Mechanistically, we show that PIK3C3 deficiency suppresses the formation of PI3P and disrupts the polarized distribution of cell-junction proteins in intestinal epithelial cells. These results not only reveal a role of PIK3C3 in gut homeostasis, but also provide a zebrafish IBD model. The functions of the class III PI3-kinase (PIK3C3) in gut homeostasis and innate immunity are poorly understood. Here the authors show that PIK3C3-deficient zebrafishes develop intestinal injury and inflammation due to mislocalization of cell junction proteins.
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20
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Bilanges B, Alliouachene S, Pearce W, Morelli D, Szabadkai G, Chung YL, Chicanne G, Valet C, Hill JM, Voshol PJ, Collinson L, Peddie C, Ali K, Ghazaly E, Rajeeve V, Trichas G, Srinivas S, Chaussade C, Salamon RS, Backer JM, Scudamore CL, Whitehead MA, Keaney EP, Murphy LO, Semple RK, Payrastre B, Tooze SA, Vanhaesebroeck B. Vps34 PI 3-kinase inactivation enhances insulin sensitivity through reprogramming of mitochondrial metabolism. Nat Commun 2017; 8:1804. [PMID: 29180704 PMCID: PMC5703854 DOI: 10.1038/s41467-017-01969-4] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2016] [Accepted: 10/30/2017] [Indexed: 12/13/2022] Open
Abstract
Vps34 PI3K is thought to be the main producer of phosphatidylinositol-3-monophosphate, a lipid that controls intracellular vesicular trafficking. The organismal impact of systemic inhibition of Vps34 kinase activity is not completely understood. Here we show that heterozygous Vps34 kinase-dead mice are healthy and display a robustly enhanced insulin sensitivity and glucose tolerance, phenotypes mimicked by a selective Vps34 inhibitor in wild-type mice. The underlying mechanism of insulin sensitization is multifactorial and not through the canonical insulin/Akt pathway. Vps34 inhibition alters cellular energy metabolism, activating the AMPK pathway in liver and muscle. In liver, Vps34 inactivation mildly dampens autophagy, limiting substrate availability for mitochondrial respiration and reducing gluconeogenesis. In muscle, Vps34 inactivation triggers a metabolic switch from oxidative phosphorylation towards glycolysis and enhanced glucose uptake. Our study identifies Vps34 as a new drug target for insulin resistance in Type-2 diabetes, in which the unmet therapeutic need remains substantial.
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Affiliation(s)
- Benoit Bilanges
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK.
| | - Samira Alliouachene
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Wayne Pearce
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Daniele Morelli
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Gyorgy Szabadkai
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, Gower Street, London, WC1E 6BT, UK
- Department of Biomedical Sciences, University of Padua, Padua, 58/B via Ugo, Bassi, 35121, Italy
| | - Yuen-Li Chung
- Cancer Research UK Cancer Imaging Centre, Division of Radiotherapy and Imaging, The Institute of Cancer Research London, 123 Old Brompton Road, London, SW7 3RP, UK
| | - Gaëtan Chicanne
- Inserm/UPS UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, 1 Avenue Jean Poulhès BP 84225, 31432, Toulouse Cedex 4, France
| | - Colin Valet
- Inserm/UPS UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, 1 Avenue Jean Poulhès BP 84225, 31432, Toulouse Cedex 4, France
| | - Julia M Hill
- Department of Cell and Developmental Biology, Consortium for Mitochondrial Research, University College London, Gower Street, London, WC1E 6BT, UK
| | - Peter J Voshol
- Metabolic Research Laboratories, MRC Metabolic Diseases Unit, Wellcome Trust-MRC Institute of Metabolic Science, Level 4, Box 289, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Lucy Collinson
- The Francis Crick Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK
| | - Christopher Peddie
- The Francis Crick Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK
| | - Khaled Ali
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Essam Ghazaly
- Centre of Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, London, EC1M 6BQ, UK
| | - Vinothini Rajeeve
- Centre of Haemato-Oncology, Barts Cancer Institute, Queen Mary University of London, London, EC1M 6BQ, UK
| | - Georgios Trichas
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK
| | - Shankar Srinivas
- Department of Physiology Anatomy and Genetics, University of Oxford, Oxford, OX1 3PT, UK
| | - Claire Chaussade
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Rachel S Salamon
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, 10461, NY, USA
| | - Jonathan M Backer
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, 10461, NY, USA
| | - Cheryl L Scudamore
- Mary Lyon Centre, MRC Harwell, Harwell Science and Innovation Campus, Harwell, OX11 0RD, UK
| | - Maria A Whitehead
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK
| | - Erin P Keaney
- Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Leon O Murphy
- Novartis Institutes for BioMedical Research, 181 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Robert K Semple
- Institute of Metabolic Science, University of Cambridge, Addenbrooke's Hospital, Cambridge, CB2 0QQ, UK
| | - Bernard Payrastre
- Inserm/UPS UMR 1048, Institut des Maladies Métaboliques et Cardiovasculaires, 1 Avenue Jean Poulhès BP 84225, 31432, Toulouse Cedex 4, France
| | - Sharon A Tooze
- The Francis Crick Institute, Lincoln's Inn Fields Laboratories, 44 Lincoln's Inn Fields, London, WC2A 3LY, UK
| | - Bart Vanhaesebroeck
- UCL Cancer Institute, University College London, 72 Huntley Street, London, WC1E 6DD, UK.
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21
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A dual role for the class III PI3K, Vps34, in platelet production and thrombus growth. Blood 2017; 130:2032-2042. [PMID: 28903944 DOI: 10.1182/blood-2017-04-781641] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Accepted: 09/01/2017] [Indexed: 12/16/2022] Open
Abstract
To uncover the role of Vps34, the sole class III phosphoinositide 3-kinase (PI3K), in megakaryocytes (MKs) and platelets, we created a mouse model with Vps34 deletion in the MK/platelet lineage (Pf4-Cre/Vps34lox/lox). Deletion of Vps34 in MKs led to the loss of its regulator protein, Vps15, and was associated with microthrombocytopenia and platelet granule abnormalities. Although Vps34 deficiency did not affect MK polyploidisation or proplatelet formation, it dampened MK granule biogenesis and directional migration toward an SDF1α gradient, leading to ectopic platelet release within the bone marrow. In MKs, the level of phosphatidylinositol 3-monophosphate (PI3P) was significantly reduced by Vps34 deletion, resulting in endocytic/trafficking defects. In platelets, the basal level of PI3P was only slightly affected by Vps34 loss, whereas the stimulation-dependent pool of PI3P was significantly decreased. Accordingly, a significant increase in the specific activity of Vps34 lipid kinase was observed after acute platelet stimulation. Similar to Vps34-deficient platelets, ex vivo treatment of wild-type mouse or human platelets with the Vps34-specific inhibitors, SAR405 and VPS34-IN1, induced abnormal secretion and affected thrombus growth at arterial shear rate, indicating a role for Vps34 kinase activity in platelet activation, independent from its role in MKs. In vivo, Vps34 deficiency had no impact on tail bleeding time, but significantly reduced platelet prothrombotic capacity after carotid injury. This study uncovers a dual role for Vps34 as a regulator of platelet production by MKs and as an unexpected regulator of platelet activation and arterial thrombus formation dynamics.
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The intricate regulation and complex functions of the Class III phosphoinositide 3-kinase Vps34. Biochem J 2017; 473:2251-71. [PMID: 27470591 DOI: 10.1042/bcj20160170] [Citation(s) in RCA: 160] [Impact Index Per Article: 22.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Accepted: 03/30/2016] [Indexed: 11/17/2022]
Abstract
The Class III phosphoinositide 3-kinase Vps34 (vacuolar protein sorting 34) plays important roles in endocytic trafficking, macroautophagy, phagocytosis, cytokinesis and nutrient sensing. Recent studies have provided exciting new insights into the structure and regulation of this lipid kinase, and new cellular functions for Vps34 have emerged. This review critically examines the wealth of new data on this important enzyme, and attempts to integrate these findings with current models of Vps34 signalling.
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Rocchi A, He C. Regulation of Exercise-Induced Autophagy in Skeletal Muscle. CURRENT PATHOBIOLOGY REPORTS 2017; 5:177-186. [PMID: 29057166 PMCID: PMC5646231 DOI: 10.1007/s40139-017-0135-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/09/2022]
Abstract
PURPOSE OF REVIEW Physical exercise is a highly effective method to prevent several pathogenic conditions, such as obesity, type 2 diabetes and cardiovascular diseases, largely due to metabolic adaptations induced by exercise in skeletal muscle. Yet how exercise induces the beneficial effects in muscle remains to be fully elucidated. Autophagy is a lysosomal degradation pathway that regulates nutrient recycling, energy production and organelle quality control. The autophagy pathway is upregulated in response to stress during exercise and muscle contraction, and may be an important mechanism mediating exercise-induced health benefits. RECENT FINDINGS A number of studies have indicated that physical exercise induces non-selective autophagy and selective mitophagy in skeletal muscle in animal models and humans. The AMPK-ULK1 and the FoxO3 signaling pathways play an essential role in the activation of the upstream autophagy machinery in skeletal muscle during exercise. The autophagy activity is required for health benefits of exercise, as in different autophagy-deficient mouse lines exercise-induced effects are abolished. SUMMARY This review aims to summarize and highlight the most recent findings on the role of autophagy in muscle maintenance, the molecular pathways that upregulate autophagy during exercise, and the potential functions of exercise-induced autophagy and mitophagy in skeletal muscle.
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Affiliation(s)
- Altea Rocchi
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Congcong He
- Department of Cell and Molecular Biology, Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
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Sabha N, Volpatti JR, Gonorazky H, Reifler A, Davidson AE, Li X, Eltayeb NM, Dall'Armi C, Di Paolo G, Brooks SV, Buj-Bello A, Feldman EL, Dowling JJ. PIK3C2B inhibition improves function and prolongs survival in myotubular myopathy animal models. J Clin Invest 2016; 126:3613-25. [PMID: 27548528 DOI: 10.1172/jci86841] [Citation(s) in RCA: 71] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2016] [Accepted: 05/19/2016] [Indexed: 11/17/2022] Open
Abstract
Myotubular myopathy (MTM) is a devastating pediatric neuromuscular disorder of phosphoinositide (PIP) metabolism resulting from mutations of the PIP phosphatase MTM1 for which there are no treatments. We have previously shown phosphatidylinositol-3-phosphate (PI3P) accumulation in animal models of MTM. Here, we tested the hypothesis that lowering PI3P levels may prevent or reverse the MTM disease process. To test this, we targeted class II and III PI3 kinases (PI3Ks) in an MTM1-deficient mouse model. Muscle-specific ablation of Pik3c2b, but not Pik3c3, resulted in complete prevention of the MTM phenotype, and postsymptomatic targeting promoted a striking rescue of disease. We confirmed this genetic interaction in zebrafish, and additionally showed that certain PI3K inhibitors prevented development of the zebrafish mtm phenotype. Finally, the PI3K inhibitor wortmannin improved motor function and prolonged lifespan of the Mtm1-deficient mice. In all, we have identified Pik3c2b as a genetic modifier of Mtm1 mutation and demonstrated that PIK3C2B inhibition is a potential treatment strategy for MTM. In addition, we set the groundwork for similar reciprocal inhibition approaches for treating other PIP metabolic disorders and highlight the importance of modifier gene pathways as therapeutic targets.
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25
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He F, Agosto MA, Anastassov IA, Tse DY, Wu SM, Wensel TG. Phosphatidylinositol-3-phosphate is light-regulated and essential for survival in retinal rods. Sci Rep 2016; 6:26978. [PMID: 27245220 PMCID: PMC4887901 DOI: 10.1038/srep26978] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Accepted: 05/10/2016] [Indexed: 11/29/2022] Open
Abstract
Phosphoinositides play important roles in numerous intracellular membrane pathways. Little is known about the regulation or function of these lipids in rod photoreceptor cells, which have highly active membrane dynamics. Using new assays with femtomole sensitivity, we determined that whereas levels of phosphatidylinositol-3,4-bisphosphate and phosphatidylinositol-3,4,5-trisphosphate were below detection limits, phosphatidylinositol-3-phosphate (PI(3)P) levels in rod inner/outer segments increased more than 30-fold after light exposure. This increase was blocked in a rod-specific knockout of the PI-3 kinase Vps34, resulting in failure of endosomal and autophagy-related membranes to fuse with lysosomes, and accumulation of abnormal membrane structures. At early ages, rods displayed normal morphology, rhodopsin trafficking, and light responses, but underwent progressive neurodegeneration with eventual loss of both rods and cones by twelve weeks. The degeneration is considerably faster than in rod knockouts of autophagy genes, indicating defects in endosome recycling or other PI(3)P-dependent membrane trafficking pathways are also essential for rod survival.
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Affiliation(s)
- Feng He
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology , Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Melina A Agosto
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology , Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Ivan A Anastassov
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology , Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA
| | - Dennis Y Tse
- Department of Ophthalmology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA.,School of Optometry, The Hong Kong Polytechnic University, Hong Kong SAR, China
| | - Samuel M Wu
- Department of Ophthalmology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
| | - Theodore G Wensel
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology , Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030, USA.,Department of Ophthalmology, Baylor College of Medicine, One Baylor Plaza, Houston, TX, 77030, USA
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26
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Valet C, Severin S, Chicanne G, Laurent PA, Gaits-Iacovoni F, Gratacap MP, Payrastre B. The role of class I, II and III PI 3-kinases in platelet production and activation and their implication in thrombosis. Adv Biol Regul 2015; 61:33-41. [PMID: 26714793 DOI: 10.1016/j.jbior.2015.11.008] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Revised: 11/23/2015] [Accepted: 11/25/2015] [Indexed: 01/13/2023]
Abstract
Blood platelets play a pivotal role in haemostasis and are strongly involved in arterial thrombosis, a leading cause of death worldwide. Besides their critical role in pathophysiology, platelets represent a valuable model to investigate, both in vitro and in vivo, the biological roles of different branches of the phosphoinositide metabolism, which is highly active in platelets. While the phospholipase C (PLC) pathway has a crucial role in platelet activation, it is now well established that at least one class I phosphoinositide 3-kinase (PI3K) is also mandatory for proper platelet functions. Except class II PI3Kγ, all other isoforms of PI3Ks (class I α, β, γ, δ; class II α, β and class III) are expressed in platelets. Class I PI3Ks have been extensively studied in different models over the past few decades and several isoforms are promising drug targets to treat cancer and immune diseases. In platelet activation, it has been shown that while class I PI3Kδ plays a minor role, class I PI3Kβ has an important function particularly in thrombus growth and stability under high shear stress conditions found in stenotic arteries. This class I PI3K is a potentially interesting target for antithrombotic strategies. The role of class I PI3Kα remains ill defined in platelets. Herein, we will discuss our recent data showing the potential impact of inhibitors of this kinase on thrombus formation. The role of class II PI3Kα and β as well as class III PI3K (Vps34) in platelet production and function is just emerging. Based on our data and those very recently published in the literature, we will discuss the impact of these three PI3K isoforms in platelet production and functions and in thrombosis.
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Affiliation(s)
- Colin Valet
- Inserm U1048, I2MC and Université Paul Sabatier, 31432, Toulouse Cedex 04, France
| | - Sonia Severin
- Inserm U1048, I2MC and Université Paul Sabatier, 31432, Toulouse Cedex 04, France
| | - Gaëtan Chicanne
- Inserm U1048, I2MC and Université Paul Sabatier, 31432, Toulouse Cedex 04, France
| | | | | | | | - Bernard Payrastre
- Inserm U1048, I2MC and Université Paul Sabatier, 31432, Toulouse Cedex 04, France; CHU de Toulouse, Laboratoire d'Hématologie, 31059, Toulouse Cedex 03, France.
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27
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Ikonomov OC, Sbrissa D, Venkatareddy M, Tisdale E, Garg P, Shisheva A. Class III PI 3-kinase is the main source of PtdIns3P substrate and membrane recruitment signal for PIKfyve constitutive function in podocyte endomembrane homeostasis. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:1240-50. [PMID: 25619930 DOI: 10.1016/j.bbamcr.2015.01.008] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/01/2014] [Revised: 12/22/2014] [Accepted: 01/16/2015] [Indexed: 11/19/2022]
Abstract
The evolutionarily conserved PIKfyve, which synthesizes PtdIns5P from PtdIns, and PtdIns(3,5)P2 from PtdIns3P, requires PtdIns3P as both an enzyme substrate and a membrane recruitment signal. Whereas the PtdIns3P source is undetermined, class III PI3K (Vps34), the only evolutionarily conserved of the eight mammalian PI3Ks, is presumed as a main candidate. A hallmark of PIKfyve deficiency is formation of multiple translucent cytoplasmic vacuoles seen by light microscopy in cells cultured in complete media. Such an aberrant phenotype is often observed in cells from conditional Vps34 knockout (KO) mice. To clarify the mechanism of Vps34 KO-triggered vacuolation and the PtdIns3P source for PIKfyve functionality, here we have characterized a podocyte cell type derived from Vps34fl/fl mice, which, upon Cre-mediated gene KO, robustly formed cytoplasmic vacuoles resembling those in PikfyveKO MEFs. Vps34wt, expressed in Vps34KO podocytes restored the normal morphology, but only if the endogenous PIKfyve activity was intact. Conversely, expressed PIKfyvewt rescued completely the vacuolation only in PikfyveKO MEFs but not in Vps34KO podocytes. Analyses of phosphoinositide profiles by HPLC and localization patterns by a PtdIns3P biosensor revealed that Vps34 is the main supplier of localized PtdIns3P not only for PIKfyve activity but also for membrane recruitment. Concordantly, Vps34KO podocytes had severely reduced steady-state levels of both PtdIns(3,5)P2 and PtdIns5P, along with PtdIns3P. We further revealed a plausible physiologically-relevant Vps34-independent PtdIns3P supply for PIKfyve, operating through activated class I PI3Ks. Our data provide the first evidence that the vacuolation phenotype in Vps34KO podocytes is due to PIKfyve dysfunction and that Vps34 is a main PtdIns3P source for constitutive PIKfyve functionality.
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Affiliation(s)
- Ognian C Ikonomov
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Diego Sbrissa
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | | | - Ellen Tisdale
- Department of Pharmacology, Wayne State University School of Medicine, Detroit, MI 48201, USA
| | - Puneet Garg
- Division of Nephrology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Assia Shisheva
- Department of Physiology, Wayne State University School of Medicine, Detroit, MI 48201, USA.
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Ravenscroft G, Laing NG, Bönnemann CG. Pathophysiological concepts in the congenital myopathies: blurring the boundaries, sharpening the focus. ACTA ACUST UNITED AC 2014; 138:246-68. [PMID: 25552303 DOI: 10.1093/brain/awu368] [Citation(s) in RCA: 63] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The congenital myopathies are a diverse group of genetic skeletal muscle diseases, which typically present at birth or in early infancy. There are multiple modes of inheritance and degrees of severity (ranging from foetal akinesia, through lethality in the newborn period to milder early and later onset cases). Classically, the congenital myopathies are defined by skeletal muscle dysfunction and a non-dystrophic muscle biopsy with the presence of one or more characteristic histological features. However, mutations in multiple different genes can cause the same pathology and mutations in the same gene can cause multiple different pathologies. This is becoming ever more apparent now that, with the increasing use of next generation sequencing, a genetic diagnosis is achieved for a greater number of patients. Thus, considerable genetic and pathological overlap is emerging, blurring the classically established boundaries. At the same time, some of the pathophysiological concepts underlying the congenital myopathies are moving into sharper focus. Here we explore whether our emerging understanding of disease pathogenesis and underlying pathophysiological mechanisms, rather than a strictly gene-centric approach, will provide grounds for a different and perhaps complementary grouping of the congenital myopathies, that at the same time could help instil the development of shared potential therapeutic approaches. Stemming from recent advances in the congenital myopathy field, five key pathophysiology themes have emerged: defects in (i) sarcolemmal and intracellular membrane remodelling and excitation-contraction coupling; (ii) mitochondrial distribution and function; (iii) myofibrillar force generation; (iv) atrophy; and (v) autophagy. Based on numerous emerging lines of evidence from recent studies in cell lines and patient tissues, mouse models and zebrafish highlighting these unifying pathophysiological themes, here we review the congenital myopathies in relation to these emerging pathophysiological concepts, highlighting both areas of overlap between established entities, as well as areas of distinction within single gene disorders.
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Affiliation(s)
- Gianina Ravenscroft
- 1 Harry Perkins Institute of Medical Research, Centre for Medical Research, University of Western Australia, Nedlands, Western Australia, Australia
| | - Nigel G Laing
- 1 Harry Perkins Institute of Medical Research, Centre for Medical Research, University of Western Australia, Nedlands, Western Australia, Australia
| | - Carsten G Bönnemann
- 2 National Institute of Neurological Disorders and Stroke/NIH, Porter Neuroscience Research Centre, Bethesda, MD, USA
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29
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Jungbluth H, Gautel M. Pathogenic mechanisms in centronuclear myopathies. Front Aging Neurosci 2014; 6:339. [PMID: 25566070 PMCID: PMC4271577 DOI: 10.3389/fnagi.2014.00339] [Citation(s) in RCA: 86] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Accepted: 12/02/2014] [Indexed: 12/30/2022] Open
Abstract
Centronuclear myopathies (CNMs) are a genetically heterogeneous group of inherited neuromuscular disorders characterized by clinical features of a congenital myopathy and abundant central nuclei as the most prominent histopathological feature. The most common forms of congenital myopathies with central nuclei have been attributed to X-linked recessive mutations in the MTM1 gene encoding myotubularin (“X-linked myotubular myopathy”), autosomal-dominant mutations in the DNM2 gene encoding dynamin-2 and the BIN1 gene encoding amphiphysin-2 (also named bridging integrator-1, BIN1, or SH3P9), and autosomal-recessive mutations in BIN1, the RYR1 gene encoding the skeletal muscle ryanodine receptor, and the TTN gene encoding titin. Models to study and rescue the affected cellular pathways are now available in yeast, C. elegans, drosophila, zebrafish, mouse, and dog. Defects in membrane trafficking have emerged as a key pathogenic mechanisms, with aberrant T-tubule formation, abnormalities of triadic assembly, and disturbance of the excitation–contraction machinery the main downstream effects studied to date. Abnormal autophagy has recently been recognized as another important collateral of defective membrane trafficking in different genetic forms of CNM, suggesting an intriguing link to primary disorders of defective autophagy with overlapping histopathological features. The following review will provide an overview of clinical, histopathological, and genetic aspects of the CNMs in the context of the key pathogenic mechanism, outline unresolved questions, and indicate promising future lines of enquiry.
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Affiliation(s)
- Heinz Jungbluth
- Neuromuscular Service, Department of Paediatric Neurology, Evelina Children's Hospital, St Thomas' Hospital , London , UK ; Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience (IoPPN), King's College London , London , UK ; Randall Division of Cell and Molecular Biophysics and Cardiovascular Division, King's College London BHF Centre of Research Excellence , London , UK
| | - Mathias Gautel
- Randall Division of Cell and Molecular Biophysics and Cardiovascular Division, King's College London BHF Centre of Research Excellence , London , UK
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