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Hedges CP, Shetty B, Broome SC, MacRae C, Koutsifeli P, Buckels EJ, MacIndoe C, Boix J, Tsiloulis T, Matthews BG, Sinha S, Arendse M, Jaiswal JK, Mellor KM, Hickey AJR, Shepherd PR, Merry TL. Dietary supplementation of clinically utilized PI3K p110α inhibitor extends the lifespan of male and female mice. Nat Aging 2023; 3:162-172. [PMID: 37118113 DOI: 10.1038/s43587-022-00349-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Accepted: 12/02/2022] [Indexed: 04/30/2023]
Abstract
Diminished insulin and insulin-like growth factor-1 signaling extends the lifespan of invertebrates1-4; however, whether it is a feasible longevity target in mammals is less clear5-12. Clinically utilized therapeutics that target this pathway, such as small-molecule inhibitors of phosphoinositide 3-kinase p110α (PI3Ki), provide a translatable approach to studying the impact of these pathways on aging. Here, we provide evidence that dietary supplementation with the PI3Ki alpelisib from middle age extends the median and maximal lifespan of mice, an effect that was more pronounced in females. While long-term PI3Ki treatment was well tolerated and led to greater strength and balance, negative impacts on common human aging markers, including reductions in bone mass and mild hyperglycemia, were also evident. These results suggest that while pharmacological suppression of insulin receptor (IR)/insulin-like growth factor receptor (IGFR) targets could represent a promising approach to delaying some aspects of aging, caution should be taken in translation to humans.
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Affiliation(s)
- C P Hedges
- Discipline of Nutrition, School of Medical Sciences, University of Auckland, Auckland, New Zealand
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
| | - B Shetty
- Discipline of Nutrition, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - S C Broome
- Discipline of Nutrition, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - C MacRae
- Discipline of Nutrition, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - P Koutsifeli
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - E J Buckels
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
- Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - C MacIndoe
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - J Boix
- Centre for Brain Research, University of Auckland, Auckland, New Zealand
| | - T Tsiloulis
- Discipline of Nutrition, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - B G Matthews
- Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - S Sinha
- Department of Pathology, Waikato Hospital, Hamilton, New Zealand
| | - M Arendse
- Department of Pathology, Waikato Hospital, Hamilton, New Zealand
| | - J K Jaiswal
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
- Auckland Cancer Society Research Centre, University of Auckland, Auckland, New Zealand
| | - K M Mellor
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
- Department of Physiology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - A J R Hickey
- Applied Surgery and Metabolism Laboratory, School of Biological Sciences, University of Auckland, Auckland, New Zealand
| | - P R Shepherd
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand
- Molecular Medicine and Pathology, School of Medical Sciences, University of Auckland, Auckland, New Zealand
| | - T L Merry
- Discipline of Nutrition, School of Medical Sciences, University of Auckland, Auckland, New Zealand.
- Maurice Wilkins Centre for Molecular Biodiscovery, University of Auckland, Auckland, New Zealand.
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Sreetama SC, Takano T, Nedergaard M, Simon SM, Jaiswal JK. Injured astrocytes are repaired by Synaptotagmin XI-regulated lysosome exocytosis. Cell Death Differ 2015; 23:596-607. [PMID: 26450452 DOI: 10.1038/cdd.2015.124] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2015] [Revised: 08/03/2015] [Accepted: 08/17/2015] [Indexed: 12/21/2022] Open
Abstract
Astrocytes are known to facilitate repair following brain injury; however, little is known about how injured astrocytes repair themselves. Repair of cell membrane injury requires Ca(2+)-triggered vesicle exocytosis. In astrocytes, lysosomes are the main Ca(2+)-regulated exocytic vesicles. Here we show that astrocyte cell membrane injury results in a large and rapid calcium increase. This triggers robust lysosome exocytosis where the fusing lysosomes release all luminal contents and merge fully with the plasma membrane. In contrast to this, receptor stimulation produces a small sustained calcium increase, which is associated with partial release of the lysosomal luminal content, and the lysosome membrane does not merge into the plasma membrane. In most cells, lysosomes express the synaptotagmin (Syt) isoform Syt VII; however, this isoform is not present on astrocyte lysosomes and exogenous expression of Syt VII on lysosome inhibits their exocytosis. Deletion of one of the most abundant Syt isoform in astrocyte--Syt XI--suppresses astrocyte lysosome exocytosis. This identifies lysosome as Syt XI-regulated exocytic vesicle in astrocytes. Further, inhibition of lysosome exocytosis (by Syt XI depletion or Syt VII expression) prevents repair of injured astrocytes. These results identify the lysosomes and Syt XI as the sub-cellular and molecular regulators, respectively of astrocyte cell membrane repair.
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Affiliation(s)
- S C Sreetama
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC, USA
| | - T Takano
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY, USA
| | - M Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY, USA
| | - S M Simon
- Laboratory of Cellular Biophysics, The Rockefeller University, 1230 York Avenue, New York, NY, USA
| | - J K Jaiswal
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC, USA.,Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, 111 Michigan Avenue NW, Washington, DC, USA
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Defour A, Van der Meulen JH, Bhat R, Bigot A, Bashir R, Nagaraju K, Jaiswal JK. Dysferlin regulates cell membrane repair by facilitating injury-triggered acid sphingomyelinase secretion. Cell Death Dis 2014; 5:e1306. [PMID: 24967968 PMCID: PMC4079937 DOI: 10.1038/cddis.2014.272] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2014] [Revised: 05/08/2014] [Accepted: 05/20/2014] [Indexed: 01/17/2023]
Abstract
Dysferlin deficiency compromises the repair of injured muscle, but the underlying cellular mechanism remains elusive. To study this phenomenon, we have developed mouse and human myoblast models for dysferlinopathy. These dysferlinopathic myoblasts undergo normal differentiation but have a deficit in their ability to repair focal injury to their cell membrane. Imaging cells undergoing repair showed that dysferlin-deficit decreased the number of lysosomes present at the cell membrane, resulting in a delay and reduction in injury-triggered lysosomal exocytosis. We find repair of injured cells does not involve formation of intracellular membrane patch through lysosome-lysosome fusion; instead, individual lysosomes fuse with the injured cell membrane, releasing acid sphingomyelinase (ASM). ASM secretion was reduced in injured dysferlinopathic cells, and acute treatment with sphingomyelinase restored the repair ability of dysferlinopathic myoblasts and myofibers. Our results provide the mechanism for dysferlin-mediated repair of skeletal muscle sarcolemma and identify ASM as a potential therapy for dysferlinopathy.
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Affiliation(s)
- A Defour
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC, USA
| | - J H Van der Meulen
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC, USA
| | - R Bhat
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC, USA
| | - A Bigot
- Institut de Myologie, UM76 Université Pierre et Marie Curie, U974 INSERM, UMR7215 CNRS, GH Pitié-Salpétrière, 47 bd de l'Hôpital, Paris, France
| | - R Bashir
- School of Biological and Biochemical Sciences, University of Durham, Durham, UK
| | - K Nagaraju
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC, USA
- Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
| | - J K Jaiswal
- Center for Genetic Medicine Research, Children's National Medical Center, 111 Michigan Avenue NW, Washington, DC, USA
- Department of Integrative Systems Biology, George Washington University School of Medicine and Health Sciences, Washington, DC, USA
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