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Saleh TA, Whitson JA, Keiser P, Prasad P, Jenkins BC, Sodeinde T, Mann C, Rabinovitch PS, McReynolds MR, Sweetwyne MT. Metabolite accumulation from oral NMN supplementation drives aging-specific kidney inflammation. bioRxiv 2024:2024.04.09.588624. [PMID: 38645109 PMCID: PMC11030441 DOI: 10.1101/2024.04.09.588624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/23/2024]
Abstract
The mitochondrial-rich renal tubule cells are key regulators of blood homeostasis via excretion and reabsorption of metabolic waste. With age, tubules are subject to increasing mitochondrial dysfunction and declining nicotinamide adenine dinucleotide (NAD+) levels, both hampering ATP production efficiency. We tested two mitochondrial interventions in young (6-mo) and aged (26-mo) adult male mice: elamipretide (ELAM), a tetrapeptide in clinical trials that improves mitochondrial structure and function, and nicotinamide mononucleotide (NMN), an NAD+ intermediate and commercially available oral supplement. Kidneys were analyzed from young and aged mice after eight weeks of treatment with ELAM (3 mg/kg/day), NMN (300 mg/kg/day), or from aged mice treated with the two interventions combined (ELAM+NMN). We hypothesized that combining pharmacologic treatments to ameliorate mitochondrial dysfunction and boost NAD+ levels, would more effectively reduce kidney aging than either intervention alone. Unexpectedly, in aged kidneys, NMN increased expression of genetic markers of inflammation (IL-1-beta; and Ccl2) and tubule injury (Kim-1). Metabolomics of endpoint sera showed that NMN-treated aged mice had higher circulating levels of uremic toxins than either aged controls or young NMN-treated mice. ELAM+NMN-treated aged mice accumulated uremic toxins like NMN-only aged mice, but reduced IL-1-beta; and Ccl2 kidney mRNA. This suggests that pre-existing mitochondrial dysfunction in aged kidney underlies susceptibility to inflammatory signaling with NMN supplementation in aged, but not young, mice. These findings demonstrate age and tissue dependent effects on downstream metabolic accumulation from NMN and highlight the need for targeted analysis of aged kidneys to assess the safety of anti-aging supplements in older populations.
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2
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Rogers CD, Kirabo A, McReynolds M, Sweetwyne MT, Wanjalla C, Benjamin J, Williams EM, Gaddy JA, Williams CR, Damo SM, Murray SA, Hinton A. The graduate school guide: How to prepare for the qualifying exam and assemble a thesis/graduate committee. J Cell Physiol 2024. [PMID: 38595027 DOI: 10.1002/jcp.31258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 03/02/2024] [Accepted: 03/05/2024] [Indexed: 04/11/2024]
Abstract
Qualifying exams and thesis committees are crucial components of a PhD candidate's journey. However, many candidates have trouble navigating these milestones and knowing what to expect. This article provides advice on meeting the requirements of the qualifying exam, understanding its format and components, choosing effective preparation strategies, retaking the qualifying exam, if necessary, and selecting a thesis committee, all while maintaining one's mental health. This comprehensive guide addresses components of the graduate school process that are often neglected.
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Affiliation(s)
- Crystal D Rogers
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis, USA
| | - Annet Kirabo
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Melanie McReynolds
- Department of Biochemistry and Molecular Biology, The Huck Institute of the Life Sciences, State College, Pennsylvania State University, University Park, Pennsylvania, USA
| | - Mariya T Sweetwyne
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, Washington, USA
| | - Celestine Wanjalla
- Department of Medicine, Division of Infectious Diseases, Vanderbilt University, Nashville, Tennessee, USA
| | - Jazmine Benjamin
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
| | - Edith M Williams
- Department of Public Health Sciences (SMD), University of Rochester, New York, Rochester, USA
| | - Jennifer A Gaddy
- Department of Medicine, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Medicine Health and Society, Vanderbilt University, Nashville, Tennessee, USA
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee, USA
- Department of Veterans Affairs, Tennessee Valley Healthcare Systems, Nashville, Tennessee, USA
| | - Clintoria R Williams
- Department of Neuroscience, Cell Biology and Physiology, Wright State University, Dayton, Ohio, USA
| | - Steven M Damo
- Department of Life and Physical Sciences, Fisk University, Nashville, Tennessee, USA
- Center for Structural Biology, Vanderbilt University, Nashville, Tennessee, USA
| | - Sandra A Murray
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, USA
| | - Antentor Hinton
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, Tennessee, USA
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3
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Crabtree A, Neikirk K, Marshall AG, Vang L, Whiteside AJ, Williams Q, Altamura CT, Owens TC, Stephens D, Shao B, Koh A, Killion M, Lopez EG, Lam J, Rodriguez B, Mungai M, Stanley J, Dean ED, Koh HJ, Gaddy JA, Scudese E, Sweetwyne MT, Davis J, Zaganjor E, Murray SA, Katti P, Damo SM, Vue Z, Hinton A. Defining Mitochondrial Cristae Morphology Changes Induced by Aging in Brown Adipose Tissue. Adv Biol (Weinh) 2024; 8:e2300186. [PMID: 37607124 PMCID: PMC10869235 DOI: 10.1002/adbi.202300186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Revised: 07/20/2023] [Indexed: 08/24/2023]
Abstract
Mitochondria are required for energy production and even give brown adipose tissue (BAT) its characteristic color due to their high iron content and abundance. The physiological function and bioenergetic capacity of mitochondria are connected to the structure, folding, and organization of its inner-membrane cristae. During the aging process, mitochondrial dysfunction is observed, and the regulatory balance of mitochondrial dynamics is often disrupted, leading to increased mitochondrial fragmentation in aging cells. Therefore, it is hypothesized that significant morphological changes in BAT mitochondria and cristae will be present with aging. A quantitative 3D electron microscopy approach is developed to map cristae network organization in mouse BAT to test this hypothesis. Using this methodology, the 3D morphology of mitochondrial cristae is investigated in adult (3-month) and aged (2-year) murine BAT tissue via serial block face-scanning electron microscopy (SBF-SEM) and 3D reconstruction software for manual segmentation, analysis, and quantification. Upon investigation, an increase is found in mitochondrial volume, surface area, and complexity and decreased sphericity in aged BAT, alongside significant decreases in cristae volume, area, perimeter, and score. Overall, these data define the nature of the mitochondrial structure in murine BAT across aging.
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Affiliation(s)
- Amber Crabtree
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Kit Neikirk
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Andrea G Marshall
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Larry Vang
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Aaron J Whiteside
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Qiana Williams
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Christopher T Altamura
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Trinity Celeste Owens
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Dominique Stephens
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Bryanna Shao
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Alice Koh
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Mason Killion
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Edgar Garza Lopez
- Department of Internal Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Jacob Lam
- Department of Internal Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Ben Rodriguez
- Department of Internal Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Margaret Mungai
- Department of Internal Medicine, University of Iowa, Iowa City, IA, 52242, USA
| | - Jade Stanley
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - E Danielle Dean
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Ho-Jin Koh
- Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, 37232, USA
| | - Jennifer A Gaddy
- Department of Biological Sciences, Tennessee State University, Nashville, TN, 37209, USA
- Tennessee Valley Healthcare Systems, U.S. Department of Veterans Affairs, Nashville, TN, 37232, USA
| | - Estevão Scudese
- Laboratory of Biosciences of Human Motricity (LABIMH), Federal University of State of Rio de Janeiro (UNIRIO), Rio de Janeiro, 22290-240, Brazil
- Sport Sciences and Exercise Laboratory (LaCEE), Catholic University of Petrópolis (UCP), Rio de Janeiro, 22290-240, Brazil
| | - Mariya T Sweetwyne
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, 98195, USA
| | - Jamaine Davis
- Department of Biochemistry, Cancer Biology, Neuroscience, Pharmacology, Meharry Medical College, Nashville, TN, 37208, USA
| | - Elma Zaganjor
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Sandra A Murray
- Department of Cell Biology, University of Pittsburgh, Pittsburg, PA, 15261, USA
| | - Prasanna Katti
- National Heart, Lung and Blood Institute, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD, 20892, USA
| | - Steven M Damo
- Department of Life and Physical Sciences, Fisk University, Nashville, TN, 37208, USA
- Center for Structural Biology, Vanderbilt University, Nashville, TN, 37232, USA
| | - Zer Vue
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
| | - Antentor Hinton
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN, 37232, USA
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4
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Vue Z, Garza‐Lopez E, Neikirk K, Katti P, Vang L, Beasley H, Shao J, Marshall AG, Crabtree A, Murphy AC, Jenkins BC, Prasad P, Evans C, Taylor B, Mungai M, Killion M, Stephens D, Christensen TA, Lam J, Rodriguez B, Phillips MA, Daneshgar N, Koh H, Koh A, Davis J, Devine N, Saleem M, Scudese E, Arnold KR, Vanessa Chavarin V, Daniel Robinson R, Chakraborty M, Gaddy JA, Sweetwyne MT, Wilson G, Zaganjor E, Kezos J, Dondi C, Reddy AK, Glancy B, Kirabo A, Quintana AM, Dai D, Ocorr K, Murray SA, Damo SM, Exil V, Riggs B, Mobley BC, Gomez JA, McReynolds MR, Hinton A. 3D reconstruction of murine mitochondria reveals changes in structure during aging linked to the MICOS complex. Aging Cell 2023; 22:e14009. [PMID: 37960952 PMCID: PMC10726809 DOI: 10.1111/acel.14009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Revised: 09/01/2023] [Accepted: 09/19/2023] [Indexed: 11/15/2023] Open
Abstract
During aging, muscle gradually undergoes sarcopenia, the loss of function associated with loss of mass, strength, endurance, and oxidative capacity. However, the 3D structural alterations of mitochondria associated with aging in skeletal muscle and cardiac tissues are not well described. Although mitochondrial aging is associated with decreased mitochondrial capacity, the genes responsible for the morphological changes in mitochondria during aging are poorly characterized. We measured changes in mitochondrial morphology in aged murine gastrocnemius, soleus, and cardiac tissues using serial block-face scanning electron microscopy and 3D reconstructions. We also used reverse transcriptase-quantitative PCR, transmission electron microscopy quantification, Seahorse analysis, and metabolomics and lipidomics to measure changes in mitochondrial morphology and function after loss of mitochondria contact site and cristae organizing system (MICOS) complex genes, Chchd3, Chchd6, and Mitofilin. We identified significant changes in mitochondrial size in aged murine gastrocnemius, soleus, and cardiac tissues. We found that both age-related loss of the MICOS complex and knockouts of MICOS genes in mice altered mitochondrial morphology. Given the critical role of mitochondria in maintaining cellular metabolism, we characterized the metabolomes and lipidomes of young and aged mouse tissues, which showed profound alterations consistent with changes in membrane integrity, supporting our observations of age-related changes in muscle tissues. We found a relationship between changes in the MICOS complex and aging. Thus, it is important to understand the mechanisms that underlie the tissue-dependent 3D mitochondrial phenotypic changes that occur in aging and the evolutionary conservation of these mechanisms between Drosophila and mammals.
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Affiliation(s)
- Zer Vue
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
| | | | - Kit Neikirk
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
| | - Prasanna Katti
- National Heart, Lung and Blood Institute, National Institutes of HealthMarylandBethesdaUSA
| | - Larry Vang
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
| | - Heather Beasley
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
| | - Jianqiang Shao
- Central Microscopy Research FacilityUniversity of IowaIowaIowa CityUSA
| | - Andrea G. Marshall
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
| | - Amber Crabtree
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
| | - Alexandria C. Murphy
- Department of Biochemistry and Molecular Biology, The Huck Institute of the Life SciencesPennsylvania State UniversityPennsylvaniaState CollegeUSA
| | - Brenita C. Jenkins
- Department of Biochemistry and Molecular Biology, The Huck Institute of the Life SciencesPennsylvania State UniversityPennsylvaniaState CollegeUSA
| | - Praveena Prasad
- Department of Biochemistry and Molecular Biology, The Huck Institute of the Life SciencesPennsylvania State UniversityPennsylvaniaState CollegeUSA
| | - Chantell Evans
- Department of Cell BiologyDuke University School of MedicineNorth CarolinaDurhamUSA
| | - Brittany Taylor
- J. Crayton Pruitt Family Department of Biomedical EngineeringUniversity of FloridaFloridaGainesvilleUSA
| | - Margaret Mungai
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
| | - Mason Killion
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
| | - Dominique Stephens
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
| | | | - Jacob Lam
- Department of Internal MedicineUniversity of IowaIowaIowa CityUSA
| | | | - Mark A. Phillips
- Department of Integrative BiologyOregon State UniversityOregonCorvallisUSA
| | - Nastaran Daneshgar
- Department of Integrative BiologyOregon State UniversityOregonCorvallisUSA
| | - Ho‐Jin Koh
- Department of Biological SciencesTennessee State UniversityTennesseeNashvilleUSA
| | - Alice Koh
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
- Department of MedicineVanderbilt University Medical CenterTennesseeNashvilleUSA
| | - Jamaine Davis
- Department of Biochemistry, Cancer Biology, Neuroscience, and PharmacologyMeharry Medical CollegeTennesseeNashvilleUSA
| | - Nina Devine
- Department of Integrative BiologyOregon State UniversityOregonCorvallisUSA
| | - Mohammad Saleem
- Department of MedicineVanderbilt University Medical CenterTennesseeNashvilleUSA
| | - Estevão Scudese
- Laboratory of Biosciences of Human Motricity (LABIMH) of the Federal University of State of Rio de Janeiro (UNIRIO)Rio de JaneiroBrazil
- Sport Sciences and Exercise Laboratory (LaCEE)Catholic University of Petrópolis (UCP)PetrópolisState of Rio de JaneiroBrazil
| | - Kenneth Ryan Arnold
- Department of Ecology and Evolutionary BiologyUniversity of California at IrvineCaliforniaIrvineUSA
| | - Valeria Vanessa Chavarin
- Department of Ecology and Evolutionary BiologyUniversity of California at IrvineCaliforniaIrvineUSA
| | - Ryan Daniel Robinson
- Department of Ecology and Evolutionary BiologyUniversity of California at IrvineCaliforniaIrvineUSA
| | | | - Jennifer A. Gaddy
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
- Department of MedicineVanderbilt University Medical CenterTennesseeNashvilleUSA
- Department of Medicine Health and SocietyVanderbilt UniversityTennesseeNashvilleUSA
- Department of Pathology, Microbiology and ImmunologyVanderbilt University Medical CenterTennesseeNashvilleUSA
- Department of Veterans AffairsTennessee Valley Healthcare SystemsTennesseeNashvilleUSA
| | - Mariya T. Sweetwyne
- Department of Laboratory Medicine and PathologyUniversity of WashingtonWashingtonSeattleUSA
| | - Genesis Wilson
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
| | - Elma Zaganjor
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
| | - James Kezos
- Sanford Burnham Prebys Medical Discovery InstituteCaliforniaLa JollaUSA
| | - Cristiana Dondi
- Sanford Burnham Prebys Medical Discovery InstituteCaliforniaLa JollaUSA
| | | | - Brian Glancy
- National Heart, Lung and Blood Institute, National Institutes of HealthMarylandBethesdaUSA
- National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of HealthMarylandBethesdaUSA
| | - Annet Kirabo
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
- Department of MedicineVanderbilt University Medical CenterTennesseeNashvilleUSA
| | - Anita M. Quintana
- Department of Biological Sciences, Border Biomedical Research CenterUniversity of Texas at El PasoTexasEl PasoUSA
| | - Dao‐Fu Dai
- Department of PathologyUniversity of Johns Hopkins School of MedicineMarylandBaltimoreUSA
| | - Karen Ocorr
- Sanford Burnham Prebys Medical Discovery InstituteCaliforniaLa JollaUSA
| | - Sandra A. Murray
- Department of Cell Biology, School of MedicineUniversity of PittsburghPennsylvaniaPittsburghUSA
| | - Steven M. Damo
- Department of Life and Physical SciencesFisk UniversityTennesseeNashvilleUSA
- Center for Structural BiologyVanderbilt UniversityTennesseeNashvilleUSA
| | - Vernat Exil
- Department of Pediatrics, Carver College of MedicineUniversity of IowaIowaIowa CityUSA
- Department of Pediatrics, Division of CardiologySt. Louis University School of MedicineMissouriSt. LouisUSA
| | - Blake Riggs
- Department of BiologySan Francisco State UniversityCaliforniaSan FranciscoUSA
| | - Bret C. Mobley
- Department of PathologyVanderbilt University Medical CenterTennesseeNashvilleUSA
| | - Jose A. Gomez
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
- Department of MedicineVanderbilt University Medical CenterTennesseeNashvilleUSA
| | - Melanie R. McReynolds
- Department of Biochemistry and Molecular Biology, The Huck Institute of the Life SciencesPennsylvania State UniversityPennsylvaniaState CollegeUSA
| | - Antentor Hinton
- Department of Molecular Physiology and BiophysicsVanderbilt UniversityTennesseeNashvilleUSA
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5
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Campbell MD, Samuelson AT, Chiao YA, Sweetwyne MT, Ladiges WC, Rabinovitch PS, Marcinek DJ. Intermittent treatment with elamipretide preserves exercise tolerance in aged female mice. GeroScience 2023; 45:2245-2255. [PMID: 36840897 PMCID: PMC10651577 DOI: 10.1007/s11357-023-00754-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 02/09/2023] [Indexed: 02/26/2023] Open
Abstract
The pathology of aging impacts multiple organ systems, including the kidney and skeletal and cardiac muscles. Long-term treatment with the mitochondrial-targeted peptide elamipretide has previously been shown to improve in vivo mitochondrial function in aged mice, which is associated with increased fatigue resistance and treadmill performance, improved cardiovascular diastolic function, and glomerular architecture of the kidney. However, elamipretide is a short tetrameric peptide that is not orally bioavailable, limiting its routes of administration. This study tested whether twice weekly intermittent injections of elamipretide could recapitulate the same functional improvements as continuous long-term infusion. We found that intermittent treatment with elamipretide for 8 months preserved exercise tolerance and left ventricular mass in mice with modest protection of diastolic function and skeletal muscle force production but did not affect kidney function as previously reported using continuous treatment.
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Affiliation(s)
- Matthew D Campbell
- Department of Radiology, University of Washington, Seattle, WA, 98109, USA
| | - Ashton T Samuelson
- Department of Radiology, University of Washington, Seattle, WA, 98109, USA
- Oregon Health Sciences Surgical Residency Program, Portland, OR, 97239, USA
| | - Ying Ann Chiao
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
- Aging & Metabolism Research Program MS21, Oklahoma Medical Research Foundation, Oklahoma City, OK, 73104, USA
| | - Mariya T Sweetwyne
- Department of Laboratory Medicine, University of Washington, Seattle, WA, 98109, USA
| | - Warren C Ladiges
- Department of Comparative Medicine, University of Washington, Seattle, WA, 98109, USA
| | - Peter S Rabinovitch
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA, USA
| | - David J Marcinek
- Department of Radiology, University of Washington, Seattle, WA, 98109, USA.
- South Lake Union Campus, 850 Republican St., Brotman D142, Box 358050, Seattle, WA, 98109, USA.
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6
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Mays A, Byars-Winston A, Hinton A, Marshall AG, Kirabo A, August A, Marlin BJ, Riggs B, Tolbert B, Wanjalla C, Womack C, Evans CS, Barnes C, Starbird C, Williams C, Reynolds C, Taabazuing C, Cameron CE, Murray DD, Applewhite D, Morton DJ, Lee D, Williams DW, Lynch D, Brady D, Lynch E, Rutaganira FUN, Silva GM, Shuler H, Saboor IA, Davis J, Dzirasa K, Hammonds-Odie L, Reyes L, Sweetwyne MT, McReynolds MR, Johnson MDL, Smith NA, Pittman N, Ajijola OA, Smith Q, Robinson RAS, Lewis SC, Murray SA, Black S, Neal SE, Andrisse S, Townsend S, Damo SM, Griffith TN, Lambert WM, Clemons WM. Juneteenth in STEMM and the barriers to equitable science. Cell 2023; 186:2510-2517. [PMID: 37295396 DOI: 10.1016/j.cell.2023.05.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 05/06/2023] [Accepted: 05/12/2023] [Indexed: 06/12/2023]
Abstract
We are 52 Black scientists. Here, we establish the context of Juneteenth in STEMM and discuss the barriers Black scientists face, the struggles they endure, and the lack of recognition they receive. We review racism's history in science and provide institutional-level solutions to reduce the burdens on Black scientists.
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Affiliation(s)
- Alfred Mays
- Burroughs Wellcome Fund, Durham, NC 27709, USA
| | - Angela Byars-Winston
- Department of Medicine, Institute for Diversity Science, University of Wisconsin-Madison, Madison, WI 53715, USA
| | - Antentor Hinton
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA.
| | - Andrea G Marshall
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA
| | - Annet Kirabo
- Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232, USA; Department of Medicine, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Vanderbilt University, Nashville, TN 37232, USA
| | - Avery August
- Department of Microbiology and Immunology, Cornell University College of Veterinary Medicine, Ithaca, NY 14853, USA
| | - Bianca J Marlin
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Psychology, Columbia University, New York, NY 10032, USA; Department of Neuroscience, Columbia University, New York, NY 10027, USA
| | - Blake Riggs
- Department of Biology, San Francisco State University, San Francisco, CA 94132, USA
| | - Blanton Tolbert
- Department of Chemistry, Case Western Reserve University, Cleveland, OH 44106, USA
| | - Celestine Wanjalla
- Division of Infectious Diseases, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Chad Womack
- National STEM Programs and Tech Initiatives at the education philanthropic charity, UNCF, Washington, DC 20001, USA
| | - Chantell S Evans
- Department of Cell Biology, Duke University Medical Center, Durham, NC 27708, USA
| | | | - Chrystal Starbird
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Clintoria Williams
- Department of Neuroscience, Cell Biology & Physiology, College of Science and Mathematics, Wright State University Boonshoft School of Medicine, Dayton, OH 45435, USA
| | - Corey Reynolds
- Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX 77030, USA; Mouse Phenotyping Core, Baylor College of Medicine, Houston, TX 77030, USA
| | - Cornelius Taabazuing
- Department of Biochemistry and Biophysics, University of Pennsylvania Perelman School of Medicine, Philadelphia, PA 19104, USA
| | - Craig E Cameron
- Department of Microbiology and Immunology, School of Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Debra D Murray
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | | | - Derrick J Morton
- Department of Biological Sciences, University of Southern California Los Angeles, Los Angeles, CA 90089, USA
| | - Dexter Lee
- Department of Physiology and Biophysics, Howard University College of Medicine, Washington, DC 20059, USA
| | - Dionna W Williams
- Department of Molecular and Comparative Pathobiology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Donald Lynch
- Department of Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati, Cincinnati, OH, USA
| | - Donita Brady
- Department of Cancer Biology, University of Pennsylvania, Philadelphia, PA 19104, USA; Abramson Family Cancer Research Institute, University of Pennsylvania, Philadelphia, PA 19104, USA; Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
| | - Erin Lynch
- University of Michigan Health System, Ann Arbor, MI 48109, USA
| | - Florentine U N Rutaganira
- Department of Biochemistry, Stanford University, Stanford, CA 94305, USA; Department of Developmental Biology, Stanford University, Stanford, CA 94305, USA
| | - Gustavo M Silva
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Haysetta Shuler
- Winston-Salem State University Department of Biological Sciences, Winston-Salem, NC 27110, USA
| | - Ishmail Abdus Saboor
- Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Biological Sciences, Columbia University, New York, NY 10027, USA.
| | - Jamaine Davis
- Department of Biochemistry, Cancer Biology, Neuroscience, Pharmacology, Meharry Medical College, Nashville, TN 37232, USA; Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA
| | - Kafui Dzirasa
- Howard Hughes Medical Institute, Chevy Chase, MD 20815, USA; Department of Psychiatry and Behavioral Sciences, Duke University Medical Center, Durham, NC 27710, USA; Department of Neurobiology, Duke University Medical Center, Durham, NC 27710, USA.
| | - Latanya Hammonds-Odie
- Department of Biological Sciences before School of Science and Technology, Georgia Gwinnett College, Lawrenceville, GA 30043, USA
| | - Loretta Reyes
- Division of Pediatric Nephrology, Emory University School of Medicine, Atlanta, GA 30322, USA
| | - Mariya T Sweetwyne
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | - Melanie R McReynolds
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA; Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA
| | - Michael D L Johnson
- Department of Immunobiology, University of Arizona, Tucson, AZ 85724, USA; BIO5 Institute, University of Arizona, Tucson, AZ 85724, USA; Valley Fever Center for Excellence, University of Arizona, Tucson, AZ, USA
| | - Nathan A Smith
- Del Monte Institute for Neuroscience, Department of Neuroscience, University of Rochester, School of Medicine and Dentistry, Rochester, NY 14642, USA
| | - Nikea Pittman
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Olujimi A Ajijola
- UCLA Cardiac Arrhythmia Center and Neurocardiology Research Program of Excellence, David Geffen School of Medicine at University of California Los Angeles, Los Angeles, CA 90095, USA
| | - Quinton Smith
- School of Engineering, University of California, Irvine, CA 92697-3975, USA
| | - Renã A S Robinson
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
| | - Samantha C Lewis
- Department of Molecular and Cellular Biology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Sandra A Murray
- Department of Cell Biology, School of Medicine, University of Pittsburgh, Pittsburgh, PA 52013, USA.
| | - Sherilynn Black
- Office of the Provost and Division of Medical Education, Duke University, Durham, NC 27708, USA.
| | - Sonya E Neal
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, La Jolla, CA 92093, USA
| | - Stanley Andrisse
- Department of Physiology and Biophysics, Howard University College of Medicine, Washington, DC 20059, USA; Department of Pediatrics, School of Medicine, Johns Hopkins University, Baltimore, MD 21287, USA
| | - Steven Townsend
- Department of Chemistry, Vanderbilt University, Nashville, TN 37235, USA
| | - Steven M Damo
- Center for Structural Biology, Vanderbilt University, Nashville, TN 37232, USA; Department of Life and Physical Sciences, Fisk University, Nashville, TN 37208, USA.
| | - Theanne N Griffith
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA 95616, USA
| | - W Marcus Lambert
- Department of Epidemiology and Biostatistics, SUNY Downstate Health Sciences University, New York, NY 11203, USA
| | - William M Clemons
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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7
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Sanchez-Contreras M, Sweetwyne MT, Tsantilas KA, Whitson JA, Campbell MD, Kohrn BF, Kim HJ, Hipp MJ, Fredrickson J, Nguyen MM, Hurley JB, Marcinek DJ, Rabinovitch PS, Kennedy SR. The multi-tissue landscape of somatic mtDNA mutations indicates tissue-specific accumulation and removal in aging. eLife 2023; 12:e83395. [PMID: 36799304 PMCID: PMC10072880 DOI: 10.7554/elife.83395] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2022] [Accepted: 02/15/2023] [Indexed: 02/18/2023] Open
Abstract
Accumulation of somatic mutations in the mitochondrial genome (mtDNA) has long been proposed as a possible mechanism of mitochondrial and tissue dysfunction that occurs during aging. A thorough characterization of age-associated mtDNA somatic mutations has been hampered by the limited ability to detect low-frequency mutations. Here, we used Duplex Sequencing on eight tissues of an aged mouse cohort to detect >89,000 independent somatic mtDNA mutations and show significant tissue-specific increases during aging across all tissues examined which did not correlate with mitochondrial content and tissue function. G→A/C→T substitutions, indicative of replication errors and/or cytidine deamination, were the predominant mutation type across all tissues and increased with age, whereas G→T/C→A substitutions, indicative of oxidative damage, were the second most common mutation type, but did not increase with age regardless of tissue. We also show that clonal expansions of mtDNA mutations with age is tissue- and mutation type-dependent. Unexpectedly, mutations associated with oxidative damage rarely formed clones in any tissue and were significantly reduced in the hearts and kidneys of aged mice treated at late age with elamipretide or nicotinamide mononucleotide. Thus, the lack of accumulation of oxidative damage-linked mutations with age suggests a life-long dynamic clearance of either the oxidative lesions or mtDNA genomes harboring oxidative damage.
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Affiliation(s)
- Monica Sanchez-Contreras
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, United States
| | - Mariya T Sweetwyne
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, United States
| | | | - Jeremy A Whitson
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, United States
| | - Matthew D Campbell
- Department of Radiology, University of Washington, Seattle, United States
| | - Brenden F Kohrn
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, United States
| | - Hyeon Jeong Kim
- Department of Biology, University of Washington, Seattle, United States
| | - Michael J Hipp
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, United States
| | - Jeanne Fredrickson
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, United States
| | - Megan M Nguyen
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, United States
| | - James B Hurley
- Department of Biochemistry, University of Washington, Seattle, United States
| | - David J Marcinek
- Department of Radiology, University of Washington, Seattle, United States
| | - Peter S Rabinovitch
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, United States
| | - Scott R Kennedy
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, United States
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8
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Sanchez-Contreras M, Sweetwyne MT, Kohrn BF, Tsantilas KA, Hipp MJ, Schmidt EK, Fredrickson J, Whitson JA, Campbell MD, Rabinovitch PS, Marcinek DJ, Kennedy SR. A replication-linked mutational gradient drives somatic mutation accumulation and influences germline polymorphisms and genome composition in mitochondrial DNA. Nucleic Acids Res 2021; 49:11103-11118. [PMID: 34614167 PMCID: PMC8565317 DOI: 10.1093/nar/gkab901] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2021] [Revised: 09/10/2021] [Accepted: 09/22/2021] [Indexed: 11/22/2022] Open
Abstract
Mutations in mitochondrial DNA (mtDNA) cause maternally inherited diseases, while somatic mutations are linked to common diseases of aging. Although mtDNA mutations impact health, the processes that give rise to them are under considerable debate. To investigate the mechanism by which de novo mutations arise, we analyzed the distribution of naturally occurring somatic mutations across the mouse and human mtDNA obtained by Duplex Sequencing. We observe distinct mutational gradients in G→A and T→C transitions delimited by the light-strand origin and the mitochondrial Control Region (mCR). The gradient increases unequally across the mtDNA with age and is lost in the absence of DNA polymerase γ proofreading activity. In addition, high-resolution analysis of the mCR shows that important regulatory elements exhibit considerable variability in mutation frequency, consistent with them being mutational ‘hot-spots’ or ‘cold-spots’. Collectively, these patterns support genome replication via a deamination prone asymmetric strand-displacement mechanism as the fundamental driver of mutagenesis in mammalian DNA. Moreover, the distribution of mtDNA single nucleotide polymorphisms in humans and the distribution of bases in the mtDNA across vertebrate species mirror this gradient, indicating that replication-linked mutations are likely the primary source of inherited polymorphisms that, over evolutionary timescales, influences genome composition during speciation.
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Affiliation(s)
- Monica Sanchez-Contreras
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | - Mariya T Sweetwyne
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | - Brendan F Kohrn
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | | | - Michael J Hipp
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | - Elizabeth K Schmidt
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | - Jeanne Fredrickson
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | - Jeremy A Whitson
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | - Matthew D Campbell
- Department of Radiology, University of Washington, Seattle, WA 98195, USA
| | - Peter S Rabinovitch
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
| | - David J Marcinek
- Department of Radiology, University of Washington, Seattle, WA 98195, USA
| | - Scott R Kennedy
- Department of Laboratory Medicine and Pathology, University of Washington, Seattle, WA 98195, USA
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9
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Tsantilas KA, Cleghorn WM, Bisbach CM, Whitson JA, Hass DT, Robbings BM, Sadilek M, Linton JD, Rountree AM, Valencia AP, Sweetwyne MT, Campbell MD, Zhang H, Jankowski CSR, Sweet IR, Marcinek DJ, Rabinovitch PS, Hurley JB. An Analysis of Metabolic Changes in the Retina and Retinal Pigment Epithelium of Aging Mice. Invest Ophthalmol Vis Sci 2021; 62:20. [PMID: 34797906 PMCID: PMC8606884 DOI: 10.1167/iovs.62.14.20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Purpose The purpose of this study was to present our hypothesis that aging alters metabolic function in ocular tissues. We tested the hypothesis by measuring metabolism in aged murine tissues alongside retinal responses to light. Methods Scotopic and photopic electroretinogram (ERG) responses in young (3–6 months) and aged (23–26 months) C57Bl/6J mice were recorded. Metabolic flux in retina and eyecup explants was quantified using U-13C-glucose or U-13C-glutamine with gas chromatography-mass spectrometry (GC-MS), O2 consumption rate (OCR) in a perifusion apparatus, and quantifying adenosine triphosphatase (ATP) with a bioluminescence assay. Results Scotopic and photopic ERG responses were reduced in aged mice. Glucose metabolism, glutamine metabolism, OCR, and ATP pools in retinal explants were mostly unaffected in aged mice. In eyecups, glutamine usage in the Krebs Cycle decreased while glucose metabolism, OCR, and ATP pools remained stable. Conclusions Our examination of metabolism showed negligible impact of age on retina and an impairment of glutamine anaplerosis in eyecups. The metabolic stability of these tissues ex vivo suggests age-related metabolic alterations may not be intrinsic. Future experiments should focus on determining whether external factors including nutrient supply, oxygen availability, or structural changes influence ocular metabolism in vivo.
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Affiliation(s)
- Kristine A Tsantilas
- Department of Biochemistry, University of Washington, Seattle, Washington, United States
| | - Whitney M Cleghorn
- Department of Biochemistry, University of Washington, Seattle, Washington, United States
| | - Celia M Bisbach
- Department of Biochemistry, University of Washington, Seattle, Washington, United States
| | - Jeremy A Whitson
- Department of Biology, Davidson College, Davidson, North Carolina, United States
| | - Daniel T Hass
- Department of Biochemistry, University of Washington, Seattle, Washington, United States
| | - Brian M Robbings
- Department of Biochemistry, University of Washington, Seattle, Washington, United States.,UW Diabetes Institute, University of Washington, Seattle, Washington, United States
| | - Martin Sadilek
- Department of Chemistry, University of Washington, Seattle, Washington, United States
| | - Jonathan D Linton
- Department of Biochemistry, University of Washington, Seattle, Washington, United States
| | - Austin M Rountree
- UW Diabetes Institute, University of Washington, Seattle, Washington, United States
| | - Ana P Valencia
- Department of Radiology, University of Washington, Seattle, Washington, United States
| | - Mariya T Sweetwyne
- Department of Laboratory Medicine & Pathology, University of Washington, Seattle, Washington, United States
| | - Matthew D Campbell
- Department of Radiology, University of Washington, Seattle, Washington, United States
| | - Huiliang Zhang
- Department of Pharmacology and Toxicology, College of Medicine, University of Arkansas for Medical Sciences, Little Rock, Arkansas, United States
| | - Connor S R Jankowski
- Department of Molecular Biology, Princeton University, Princeton, New Jersey, United States.,Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey, United States
| | - Ian R Sweet
- UW Diabetes Institute, University of Washington, Seattle, Washington, United States
| | - David J Marcinek
- Department of Radiology, University of Washington, Seattle, Washington, United States
| | - Peter S Rabinovitch
- Department of Laboratory Medicine & Pathology, University of Washington, Seattle, Washington, United States
| | - James B Hurley
- Department of Biochemistry, University of Washington, Seattle, Washington, United States.,Department of Ophthalmology, University of Washington, Seattle, Washington, United States
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10
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Whitson JA, Bitto A, Zhang H, Sweetwyne MT, Coig R, Bhayana S, Shankland EG, Wang L, Bammler TK, Mills KF, Imai S, Conley KE, Marcinek DJ, Rabinovitch PS. SS-31 and NMN: Two paths to improve metabolism and function in aged hearts. Aging Cell 2020; 19:e13213. [PMID: 32779818 PMCID: PMC7576234 DOI: 10.1111/acel.13213] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Revised: 06/16/2020] [Accepted: 07/13/2020] [Indexed: 12/14/2022] Open
Abstract
The effects of two different mitochondrial-targeted drugs, SS-31 and NMN, were tested on Old mouse hearts. After treatment with the drugs, individually or Combined, heart function was examined by echocardiography. SS-31 partially reversed an age-related decline in diastolic function while NMN fully reversed an age-related deficiency in systolic function at a higher workload. Metabolomic analysis revealed that both NMN and the Combined treatment increased nicotinamide and 1-methylnicotinamide levels, indicating greater NAD+ turnover, but only the Combined treatment resulted in significantly greater steady-state NAD(H) levels. A novel magnetic resonance spectroscopy approach was used to assess how metabolite levels responded to changing cardiac workload. PCr/ATP decreased in response to increased workload in Old Control, but not Young, hearts, indicating an age-related decline in energetic capacity. Both drugs were able to normalize the PCr/ATP dynamics. SS-31 and NMN treatment also increased mitochondrial NAD(P)H production under the higher workload, while only NMN increased NAD+ in response to increased work. These measures did not shift in hearts given the Combined treatment, which may be owed to the enhanced NAD(H) levels in the resting state after this treatment. Overall, these results indicate that both drugs are effective at restoring different aspects of mitochondrial and heart health and that combining them results in a synergistic effect that rejuvenates Old hearts and best recapitulates the Young state.
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Affiliation(s)
- Jeremy A. Whitson
- Department of Laboratory Medicine and PathologyUniversity of WashingtonSeattleWashingtonUSA
| | - Alessandro Bitto
- Department of Laboratory Medicine and PathologyUniversity of WashingtonSeattleWashingtonUSA
| | - Huiliang Zhang
- Department of Laboratory Medicine and PathologyUniversity of WashingtonSeattleWashingtonUSA
| | - Mariya T. Sweetwyne
- Department of Laboratory Medicine and PathologyUniversity of WashingtonSeattleWashingtonUSA
| | - Rene Coig
- Department of Laboratory Medicine and PathologyUniversity of WashingtonSeattleWashingtonUSA
| | - Saakshi Bhayana
- Department of RadiologyUniversity of WashingtonSeattleWashingtonUSA
| | | | - Lu Wang
- Department of Environmental & Occupational Health SciencesUniversity of WashingtonSeattleWashingtonUSA
| | - Theo K. Bammler
- Department of Environmental & Occupational Health SciencesUniversity of WashingtonSeattleWashingtonUSA
| | - Kathryn F. Mills
- Department of Developmental BiologyWashington University School of MedicineSt. LouisMissouriUSA
| | - Shin‐Ichiro Imai
- Department of Developmental BiologyWashington University School of MedicineSt. LouisMissouriUSA
| | - Kevin E. Conley
- Department of RadiologyUniversity of WashingtonSeattleWashingtonUSA
| | | | - Peter S. Rabinovitch
- Department of Laboratory Medicine and PathologyUniversity of WashingtonSeattleWashingtonUSA
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11
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Quarles E, Basisty N, Chiao YA, Merrihew G, Gu H, Sweetwyne MT, Fredrickson J, Nguyen N, Razumova M, Kooiker K, Moussavi‐Harami F, Regnier M, Quarles C, MacCoss M, Rabinovitch PS. Rapamycin persistently improves cardiac function in aged, male and female mice, even following cessation of treatment. Aging Cell 2020; 19:e13086. [PMID: 31823466 PMCID: PMC6996961 DOI: 10.1111/acel.13086] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 11/12/2019] [Accepted: 11/13/2019] [Indexed: 12/29/2022] Open
Abstract
Even in healthy aging, cardiac morbidity and mortality increase with age in both mice and humans. These effects include a decline in diastolic function, left ventricular hypertrophy, metabolic substrate shifts, and alterations in the cardiac proteome. Previous work from our laboratory indicated that short-term (10-week) treatment with rapamycin, an mTORC1 inhibitor, improved measures of these age-related changes. In this report, we demonstrate that the rapamycin-dependent improvement of diastolic function is highly persistent, while decreases in both cardiac hypertrophy and passive stiffness are substantially persistent 8 weeks after cessation of an 8-week treatment of rapamycin in both male and female 22- to 24-month-old C57BL/6NIA mice. The proteomic and metabolomic abundance changes that occur after 8 weeks of rapamycin treatment have varying persistence after 8 further weeks without the drug. However, rapamycin did lead to a persistent increase in abundance of electron transport chain (ETC) complex components, most of which belonged to Complex I. Although ETC protein abundance and Complex I activity were each differentially affected in males and females, the ratio of Complex I activity to Complex I protein abundance was equally and persistently reduced after rapamycin treatment in both sexes. Thus, rapamycin treatment in the aged mice persistently improved diastolic function and myocardial stiffness, persistently altered the cardiac proteome in the absence of persistent metabolic changes, and led to persistent alterations in mitochondrial respiratory chain activity. These observations suggest that an optimal translational regimen for rapamycin therapy that promotes enhancement of healthspan may involve intermittent short-term treatments.
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Affiliation(s)
- Ellen Quarles
- Department of PathologyUniversity of WashingtonSeattleWAUSA
- Present address:
University of MichiganAnn ArborMIUSA
| | - Nathan Basisty
- Department of PathologyUniversity of WashingtonSeattleWAUSA
- Present address:
Buck Institute of AgingNovatoCAUSA
| | - Ying Ann Chiao
- Department of PathologyUniversity of WashingtonSeattleWAUSA
- Present address:
Oklahoma Medical Research FoundationOklahoma CityOKUSA
| | | | - Haiwei Gu
- Department of Anesthesiology and Pain MedicineUniversity of WashingtonSeattleWAUSA
| | | | | | | | - Maria Razumova
- Department of BioengineeringUniversity of WashingtonSeattleWAUSA
| | - Kristina Kooiker
- Division of CardiologyDepartment of MedicineUniversity of WashingtonSeattleWAUSA
| | | | - Michael Regnier
- Department of BioengineeringUniversity of WashingtonSeattleWAUSA
| | - Christopher Quarles
- School of InformationUniversity of MichiganAnn ArborMIUSA
- Present address:
University of MichiganAnn ArborMIUSA
| | - Michael MacCoss
- Department of Genome SciencesUniversity of WashingtonSeattleWAUSA
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12
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Sweetwyne MT, Pippin JW, Eng DG, Hudkins KL, Chiao YA, Campbell MD, Marcinek DJ, Alpers CE, Szeto HH, Rabinovitch PS, Shankland SJ. The mitochondrial-targeted peptide, SS-31, improves glomerular architecture in mice of advanced age. Kidney Int 2017; 91:1126-1145. [PMID: 28063595 DOI: 10.1016/j.kint.2016.10.036] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 10/09/2016] [Accepted: 10/27/2016] [Indexed: 01/12/2023]
Abstract
Although age-associated changes in kidney glomerular architecture have been described in mice and man, the mechanisms are unknown. It is unclear if these changes can be prevented or even reversed by systemic therapies administered at advanced age. Using light microscopy and transmission electron microscopy, our results showed glomerulosclerosis with injury to mitochondria in glomerular epithelial cells in mice aged 26 months (equivalent to a 79-year-old human). To test the hypothesis that reducing mitochondrial damage in late age would result in lowered glomerulosclerosis, we administered the mitochondrial targeted peptide, SS-31, to aged mice. Baseline (24-month-old) mice were randomized to receive 8 weeks of SS-31, or saline, and killed at 26 months of age. SS-31 treatment improved age-related mitochondrial morphology and glomerulosclerosis. Assessment of glomeruli revealed that SS-31 reduced senescence (p16, senescence-associated-ß-Gal) and increased the density of parietal epithelial cells. However, SS-31 treatment reduced markers of parietal epithelial cell activation (Collagen IV, pERK1/2, and α-smooth muscle actin). SS-31 did not impact podocyte density, but it reduced markers of podocyte injury (desmin) and improved cytoskeletal integrity (synaptopodin). This was accompanied by higher glomerular endothelial cell density (CD31). Thus, despite initiating therapy in late-age mice, a short course of SS-31 has protective benefits on glomerular mitochondria, accompanied by temporal changes to the glomerular architecture. This systemic pharmacological intervention in old-aged animals limits glomerulosclerosis and senescence, reduces parietal epithelial cell activation, and improves podocyte and endothelial cell integrity.
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Affiliation(s)
| | - Jeffrey W Pippin
- Division of Nephrology, University of Washington, Seattle, WA, USA
| | - Diana G Eng
- Division of Nephrology, University of Washington, Seattle, WA, USA
| | - Kelly L Hudkins
- Department of Pathology, University of Washington, Seattle, WA, USA
| | - Ying Ann Chiao
- Department of Pathology, University of Washington, Seattle, WA, USA
| | | | - David J Marcinek
- Department of Radiology, University of Washington, Seattle, WA, USA
| | - Charles E Alpers
- Department of Pathology, University of Washington, Seattle, WA, USA
| | - Hazel H Szeto
- Department of Pharmacology, Weill Cornell Medical College, New York, NY, USA
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13
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Sweetwyne MT, Brekken RA, Workman G, Bradshaw AD, Carbon J, Siadak AW, Murri C, Sage EH. Functional Analysis of the Matricellular Protein SPARC with Novel Monoclonal Antibodies. J Histochem Cytochem 2016; 52:723-33. [PMID: 15150281 DOI: 10.1369/jhc.3a6153.2004] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
SPARC (osteonectin, BM-40) is a matricellular glycoprotein that is expressed in many embryogenic and adult tissues undergoing remodeling or repair. SPARC modulates cellular interaction with the extracellular matrix (ECM), inhibits cell adhesion and proliferation, and regulates growth factor activity. To explore further the function and activity of this protein in tissue homeostasis, we have developed several monoclonal antibodies (MAbs) that recognize distinct epitopes on SPARC. The MAbs bind to SPARC with high affinity and identify SPARC by ELISA, Western blotting, immunoprecipitation, immunocytochemistry, and/or immunohistochemistry. The MAbs were also characterized in functional assays for potential alteration of SPARC activity. SPARC binds to collagen I and laminin-1 through an epitope defined by MAb 293; this epitope is not involved in the binding of SPARC to collagen III. The other MAbs did not interfere with the binding of SPARC to collagen I or III or laminin-1. Inhibition of the anti-adhesive effect of SPARC on endothelial cells by MAb 236 was also observed. Functional analysis of SPARC in the presence of these novel MAbs now confirms that the activities ascribed to this matricellular protein can be assigned to discrete subdomains.
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Affiliation(s)
- Mariya T Sweetwyne
- Department of Vascular Biology, The Hope Heart Institute, Seattle, Washington 98101, USA
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14
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Sweetwyne MT, Gruenwald A, Niranjan T, Nishinakamura R, Strobl LJ, Susztak K. Notch1 and Notch2 in Podocytes Play Differential Roles During Diabetic Nephropathy Development. Diabetes 2015; 64:4099-111. [PMID: 26293507 PMCID: PMC4657584 DOI: 10.2337/db15-0260] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [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] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2015] [Accepted: 08/04/2015] [Indexed: 12/29/2022]
Abstract
Notch pathway activation in podocytes has been shown to play an important role in diabetic kidney disease (DKD) development; however, the receptors and ligands involved in the process have not been identified. Here, we report that conditional deletion of Notch1 in podocytes using NPHS2(cre)Notch1(flox/flox) animals resulted in marked amelioration of DKD. On the contrary, podocyte-specific genetic deletion of Notch2 had no effect on albuminuria and mesangial expansion. Notch1-null podocytes were protected from apoptosis and dedifferentiation in vitro, likely explaining the protective phenotype in vivo. Deletion of Notch1 in podocytes also resulted in an increase in Notch2 expression, indicating an interaction between the receptors. At the same time, transgenic overexpression of Notch2 in podocytes did not induce phenotypic changes, while constitutive expression of Notch1 caused rapid development of albuminuria and glomerulosclerosis. In summary, our studies indicate that Notch1 plays a distinct (nonredundant) role in podocytes during DKD development.
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MESH Headings
- Animals
- Apoptosis
- Biomarkers/metabolism
- Cell Dedifferentiation
- Cell Line, Transformed
- Cells, Cultured
- Crosses, Genetic
- Diabetic Nephropathies/metabolism
- Diabetic Nephropathies/pathology
- Diabetic Nephropathies/prevention & control
- Glomerular Mesangium/metabolism
- Glomerular Mesangium/pathology
- Male
- Mice, Inbred C57BL
- Mice, Knockout
- Mice, Transgenic
- Peptide Fragments/genetics
- Peptide Fragments/metabolism
- Podocytes/metabolism
- Podocytes/pathology
- Protein Interaction Domains and Motifs
- RNA, Messenger/metabolism
- Receptor, Notch1/chemistry
- Receptor, Notch1/genetics
- Receptor, Notch1/metabolism
- Receptor, Notch2/chemistry
- Receptor, Notch2/genetics
- Receptor, Notch2/metabolism
- Recombinant Proteins/chemistry
- Recombinant Proteins/metabolism
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Affiliation(s)
- Mariya T Sweetwyne
- Renal Electrolyte and Hypertension Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Antje Gruenwald
- Renal Electrolyte and Hypertension Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Thiruvur Niranjan
- Renal Electrolyte and Hypertension Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Ryuichi Nishinakamura
- Department of Kidney Development, Institute of Molecular Embryology and Genetics, Kumamoto University, Kumamoto, Japan
| | - Lothar J Strobl
- Department of Gene Vectors, Helmholtz Center Munich, German Research Center for Environmental Health, Munich, Germany
| | - Katalin Susztak
- Renal Electrolyte and Hypertension Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
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15
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Na J, Sweetwyne MT, Park ASD, Susztak K, Cagan RL. Diet-Induced Podocyte Dysfunction in Drosophila and Mammals. Cell Rep 2015; 12:636-47. [PMID: 26190114 DOI: 10.1016/j.celrep.2015.06.056] [Citation(s) in RCA: 67] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2014] [Revised: 05/15/2015] [Accepted: 06/17/2015] [Indexed: 01/15/2023] Open
Abstract
Diabetic nephropathy is a major cause of end-stage kidney disease. Characterized by progressive microvascular disease, most efforts have focused on injury to the glomerular endothelium. Recent work has suggested a role for the podocyte, a highly specialized component of the glomerular filtration barrier. Here, we demonstrate that the Drosophila nephrocyte, a cell analogous to the mammalian podocyte, displays defects that phenocopy aspects of diabetic nephropathy in animals fed chronic high dietary sucrose. Through functional studies, we identify an OGT-Polycomb-Knot-Sns pathway that links dietary sucrose to loss of the Nephrin ortholog Sns. Reducing OGT through genetic or drug means is sufficient to rescue loss of Sns, leading to overall extension of lifespan. We demonstrate upregulation of the Knot ortholog EBF2 in glomeruli of human diabetic nephropathy patients and a mouse ob/ob diabetes model. Furthermore, we demonstrate rescue of Nephrin expression and cell viability in ebf2(-/-) primary podocytes cultured in high glucose.
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Affiliation(s)
- Jianbo Na
- Department of Developmental and Regenerative Biology and School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029-1020, USA
| | - Mariya T Sweetwyne
- Renal Electrolyte and Hypertension Division, Perelman School of Medicine, University of Pennsylvania, 415 Curie Boulevard, 405B Clinical Research Building, Philadelphia, PA 19104-4539, USA
| | - Ae Seo Deok Park
- Renal Electrolyte and Hypertension Division, Perelman School of Medicine, University of Pennsylvania, 415 Curie Boulevard, 405B Clinical Research Building, Philadelphia, PA 19104-4539, USA
| | - Katalin Susztak
- Renal Electrolyte and Hypertension Division, Perelman School of Medicine, University of Pennsylvania, 415 Curie Boulevard, 405B Clinical Research Building, Philadelphia, PA 19104-4539, USA
| | - Ross L Cagan
- Department of Developmental and Regenerative Biology and School of Biomedical Sciences, Icahn School of Medicine at Mount Sinai, One Gustave Levy Place, New York, NY 10029-1020, USA.
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Abstract
Notch is a critical regulator of kidney development, but the pathway is mostly silenced once kidney maturation is achieved. Recent reports demonstrated increased expression of Notch receptors and ligands both in acute and chronic kidney injury. In vivo studies indicated that Notch activation might contribute to regeneration after acute kidney injury; on the other hand, sustained Notch expression is causally associated with interstitial fibrosis and glomerulosclerosis. This review will summarize the current knowledge on the role of the Notch signaling with special focus on kidney fibrosis.
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Affiliation(s)
- Mariya T Sweetwyne
- Renal Electrolyte and Hypertension Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania, USA
| | - Jianling Tao
- Renal Electrolyte and Hypertension Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania, USA
| | - Katalin Susztak
- Renal Electrolyte and Hypertension Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania , Philadelphia, Pennsylvania, USA
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17
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Zhu F, Sweetwyne MT, Hankenson KD. PKCδ is required for Jagged-1 induction of human mesenchymal stem cell osteogenic differentiation. Stem Cells 2014; 31:1181-92. [PMID: 23404789 DOI: 10.1002/stem.1353] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 12/29/2012] [Indexed: 12/22/2022]
Abstract
JAG1, the gene for the Jagged-1 ligand (Jag1) in the Notch signaling pathway, is variably mutated in Alagille Syndrome (ALGS). ALGS patients have skeletal defects, and additionally JAG1 has been shown to be associated with low bone mass through genome-wide association studies. Plating human osteoblast precursors (human mesenchymal stem cells-hMSCs) on Jag1 is sufficient to induce osteoblast differentiation; however, exposure of mouse MSC (mMSC) to Jag1 actually inhibits osteoblastogenesis. Overexpression of the notch-2 intracellular domain (NICD2) is sufficient to mimic the effect of Jag1 on hMSC osteoblastogenesis, while blocking Notch signaling with a γ-secretase inhibitor or with dominant-negative mastermind inhibits Jag1-induced hMSC osteoblastogenesis. In pursuit of interacting signaling pathways, we discovered that treatment with a protein kinase C δ (PKCδ) inhibitor abrogates Jag1-induced hMSC osteoblastogenesis. Jag1 results in rapid PKCδ nuclear translocation and kinase activation. Furthermore, Jag1 stimulates the physical interaction of PKCδ with NICD. Collectively, these results suggest that Jag1 induces hMSC osteoblast differentiation through canonical Notch signaling and requires concomitant PKCδ signaling. This research also demonstrates potential deficiencies in using mouse models to study ALGS bone abnormalities.
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Affiliation(s)
- Fengchang Zhu
- Department of Clinical Studies-New Bolton Center, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
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18
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Brennan TA, Egan KP, Lindborg CM, Chen Q, Sweetwyne MT, Hankenson KD, Xie SX, Johnson FB, Pignolo RJ. Mouse models of telomere dysfunction phenocopy skeletal changes found in human age-related osteoporosis. Dis Model Mech 2014; 7:583-92. [PMID: 24626990 PMCID: PMC4007409 DOI: 10.1242/dmm.014928] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
A major medical challenge in the elderly is osteoporosis and the high risk of fracture. Telomere dysfunction is a cause of cellular senescence and telomere shortening, which occurs with age in cells from most human tissues, including bone. Telomere defects contribute to the pathogenesis of two progeroid disorders characterized by premature osteoporosis, Werner syndrome and dyskeratosis congenital. It is hypothesized that telomere shortening contributes to bone aging. We evaluated the skeletal phenotypes of mice with disrupted telomere maintenance mechanisms as models for human bone aging, including mutants in Werner helicase (Wrn−/−), telomerase (Terc−/−) and Wrn−/−Terc−/− double mutants. Compared with young wild-type (WT) mice, micro-computerized tomography analysis revealed that young Terc−/− and Wrn−/−Terc−/− mice have decreased trabecular bone volume, trabecular number and trabecular thickness, as well as increased trabecular spacing. In cortical bone, young Terc−/− and Wrn−/−Terc−/− mice have increased cortical thinning, and increased porosity relative to age-matched WT mice. These trabecular and cortical changes were accelerated with age in Terc−/− and Wrn−/−Terc−/− mice compared with older WT mice. Histological quantification of osteoblasts in aged mice showed a similar number of osteoblasts in all genotypes; however, significant decreases in osteoid, mineralization surface, mineral apposition rate and bone formation rate in older Terc−/− and Wrn−/−Terc−/− bone suggest that osteoblast dysfunction is a prominent feature of precocious aging in these mice. Except in the Wrn−/− single mutant, osteoclast number did not increase in any genotype. Significant alterations in mechanical parameters (structure model index, degree of anistrophy and moment of inertia) of the Terc−/− and Wrn−/−Terc−/− femurs compared with WT mice were also observed. Young Wrn−/−Terc−/− mice had a statistically significant increase in bone-marrow fat content compared with young WT mice, which remained elevated in aged double mutants. Taken together, our results suggest that Terc−/− and Wrn−/−Terc−/− mutants recapitulate the human bone aging phenotype and are useful models for studying age-related osteoporosis.
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Affiliation(s)
- Tracy A Brennan
- Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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19
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Abstract
Podocyte (glomerular epithelial cell; GEC) dysfunction and loss are the hallmarks of focal segmental glomerulosclerosis (FSGS). Over the recent years, changes, including activation and proliferation of parietal epithelial cells (PEC) have been increasingly appreciated in FSGS. The functional role of PECs in FSGS is still a hotly debated issue. Here Ueno et al. report that Notch signaling plays a role in orchestrating PEC cell phenotypic changes in FSGS.
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Affiliation(s)
- Mariya T Sweetwyne
- Renal, Electrolyte and Hypertension Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6144, USA
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20
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Sweetwyne MT, Murphy-Ullrich JE. Thrombospondin1 in tissue repair and fibrosis: TGF-β-dependent and independent mechanisms. Matrix Biol 2012; 31:178-86. [PMID: 22266026 DOI: 10.1016/j.matbio.2012.01.006] [Citation(s) in RCA: 163] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 12/20/2011] [Accepted: 12/22/2011] [Indexed: 12/16/2022]
Abstract
Thrombospondin 1 (TSP1) plays major roles in both physiologic and pathologic tissue repair. TSP1 through its type 1 repeats is a known regulator of latent TGF-β activation and plays a role in wound healing and fibrosis. Binding of the TSP N-terminal domain to cell surface calreticulin in complex with LDL-receptor related protein 1 stimulates intermediate cell adhesion, cell migration, anoikis resistance, collagen expression and matrix deposition in an in vivo model of the foreign body response. There is also emerging evidence that TSP EGF-like repeats alter endothelial cell-cell interactions and stimulate epithelial migration through transactivation of EGF receptors. The mechanisms underlying these functions of TSP1 and the implications for physiologic and pathologic wound repair and fibrosis will be discussed.
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Affiliation(s)
- Mariya T Sweetwyne
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, United States
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21
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Sweetwyne MT, Pallero MA, Lu A, Van Duyn Graham L, Murphy-Ullrich JE. The calreticulin-binding sequence of thrombospondin 1 regulates collagen expression and organization during tissue remodeling. Am J Pathol 2010; 177:1710-24. [PMID: 20724603 DOI: 10.2353/ajpath.2010.090903] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Amino acids 17-35 of the thrombospondin1 (TSP1) N-terminal domain (NTD) bind cell surface calreticulin to signal focal adhesion disassembly, cell migration, and anoikis resistance in vitro. However, the in vivo relevance of this signaling pathway has not been previously determined. We engineered local in vivo expression of the TSP1 calreticulin-binding sequence to determine the role of TSP1 in tissue remodeling. Surgical sponges impregnated with a plasmid encoding the secreted calreticulin-binding sequence [NTD (1-35)-EGFP] or a control sequence [mod NTD (1-35)-EGFP] tagged with enhanced green fluorescent protein were implanted subcutaneously in mice. Sponges expressing NTD (1-35)-EFGP formed a highly organized capsule despite no differences in cellular composition, suggesting stimulation of collagen deposition by the calreticulin-binding sequence of TSP1. TSP1, recombinant NTD, or a peptide of the TSP1 calreticulin-binding sequence (hep I) increased both collagen expression and matrix deposition by fibroblasts in vitro. TSP1 stimulation of collagen was inhibited by a peptide that blocks TSP1 binding to calreticulin, demonstrating the requirement for cell surface calreticulin. Collagen stimulation was independent of TGF-β activity and Smad phosphorylation but was blocked by an Akt inhibitor, suggesting that signaling through the Akt pathway is important for regulation of collagen through TSP1 binding to calreticulin. These studies identify a novel function for the NTD of TSP1 as a mediator of collagen expression and deposition during tissue remodeling.
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Affiliation(s)
- Mariya T Sweetwyne
- Departments of Cell Biology, University of Alabama, Birmingham, Birmingham, Alabama 35294-0019, USA
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22
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Abstract
Thrombospondins (TSPs) are a family of five secreted multimeric matricellular proteins that share homology in the type II and III repeats and carboxy-terminal region. Type I repeats, also known as properdin or thrombospondin repeats (TSRs), are found in TSP1/2, but not TSP3-5. A variety of other secreted proteins contain TSRs, including the novel extracellular molecules, R-spondins. TSP family and many TSR-containing proteins, including R-spondins, are highly expressed in skeletal tissues during development and postnatal. TSP2 regulates the osteoblast lineage, influencing bone mass and geometry, as well as response to fracture healing, ovariectomy, and mechanical loading. Compound knockout mice of TSPs have revealed important mechanistic insights. TSP1/2 knockout mice have craniofacial dysmorphism, and TSP1/3/5 compound knockout mice display growth plate abnormalities. R-spondins promote osteoblast differentiation and R-spondin-2 deficiency results in skeletal developmental defects. Overall, TSP and other TSR molecules influence multiple aspects of bone development and remodeling.
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Affiliation(s)
- Kurt D Hankenson
- Department of Animal Biology, School of Veterinary Medicine, University of Pennsylvania, 311 Hill Pavilion, 380 South University Avenue, Philadelphia, PA, 19104-4539, USA.
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23
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Van Duyn Graham L, Sweetwyne MT, Pallero MA, Murphy-Ullrich JE. Intracellular calreticulin regulates multiple steps in fibrillar collagen expression, trafficking, and processing into the extracellular matrix. J Biol Chem 2010; 285:7067-78. [PMID: 20044481 PMCID: PMC2844156 DOI: 10.1074/jbc.m109.006841] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Revised: 12/29/2009] [Indexed: 12/19/2022] Open
Abstract
Calreticulin (CRT), a chaperone and Ca(2+) regulator, enhances wound healing, and its expression correlates with fibrosis in animal models, suggesting that CRT regulates production of the extracellular matrix. However, direct regulation of collagen matrix by CRT has not been previously demonstrated. We investigated the role of CRT in the regulation of fibrillar collagen expression, secretion, processing, and deposition in the extracellular matrix by fibroblasts. Mouse embryonic fibroblasts deficient in CRT (CRT(-/-) MEFs) have reduced transcript levels of fibrillar collagen I and III and less soluble collagen as compared with wild type MEFs. Correspondingly, fibroblasts engineered to overexpress CRT have increased collagen type I transcript and protein. Collagen expression appears to be regulated by endoplasmic reticulum (ER) calcium levels and intracellular CRT, because thapsigargin treatment reduced collagen expression, whereas addition of exogenous recombinant CRT had no effect. CRT(-/-) MEFs exhibited increased ER retention of collagen, and collagen and CRT were co-immunoprecipitated from isolated cell lysates, suggesting that CRT is important for trafficking of collagen through the ER. CRT(-/-) MEFs also have reduced type I procollagen processing and deposition into the extracellular matrix. The reduced collagen matrix deposition is partly a consequence of reduced fibronectin matrix formation in the CRT-deficient cells. Together, these data show that CRT complexes with collagen in cells and that CRT plays critical roles at multiple stages of collagen expression and processing. These data identify CRT as an important regulator of collagen and suggest that intracellular CRT signaling plays an important role in tissue remodeling and fibrosis.
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Affiliation(s)
| | - Mariya T. Sweetwyne
- Cell Biology, University of Alabama at Birmingham, Birmingham, Alabama 35294-0019
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24
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Gold LI, Eggleton P, Sweetwyne MT, Van Duyn LB, Greives MR, Naylor SM, Michalak M, Murphy-Ullrich JE. Calreticulin: non-endoplasmic reticulum functions in physiology and disease. FASEB J 2009; 24:665-83. [PMID: 19940256 DOI: 10.1096/fj.09-145482] [Citation(s) in RCA: 299] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Calreticulin (CRT), when localized to the endoplasmic reticulum (ER), has important functions in directing proper conformation of proteins and glycoproteins, as well as in homeostatic control of cytosolic and ER calcium levels. There is also steadily accumulating evidence for diverse roles for CRT localized outside the ER, including data suggesting important roles for CRT localized to the outer cell surface of a variety of cell types, in the cytosol, and in the extracellular matrix (ECM). Furthermore, the addition of exogenous CRT rescues numerous CRT-driven functions, such as adhesion, migration, phagocytosis, and immunoregulatory functions of CRT-null cells. Recent studies show that topically applied CRT has diverse and profound biological effects that enhance cutaneous wound healing in animal models. This evidence for extracellular bioactivities of CRT has provided new insights into this classically ER-resident protein, despite a lack of knowledge of how CRT exits from the ER to the cell surface or how it is released into the extracellular milieu. Nonetheless, it has become clear that CRT is a multicompartmental protein that regulates a wide array of cellular responses important in physiological and pathological processes, such as wound healing, the immune response, fibrosis, and cancer.-Gold, L. I., Eggleton, P., Sweetwyne, M. T., Van Duyn, L. B., Greives, M. R., Naylor, S.-M., Michalak, M., Murphy-Ullrich, J. E. Calreticulin: non-endoplamic reticulum functions in physiology and disease.
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Affiliation(s)
- Leslie I Gold
- Departments of Medicine and Pathology, New York, University School of Medicine, 550 First Ave., NB16S13 New York, NY 10016 USA.
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25
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Van Duyn LB, Sweetwyne MT, Murphy-Ullrich JE. Calreticulin plays a role in collagen regulation. Matrix Biol 2008. [DOI: 10.1016/j.matbio.2008.09.294] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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