Benefits of Metformin in Attenuating the Hallmarks of Aging

Ameya S. Kulkarni,1,2, * Sriram Gubbi,3 and Nir Barzilai1,2

1Institute for Aging Research, Albert Einstein College of Medicine, Bronx, New York, NY, USA

2Department of Medicine, Division of Endocrinology, Albert Einstein College of Medicine, Bronx, New York, NY, USA

3Metabolic Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, USA

*Correspondence: 该Email地址已收到反垃圾邮件插件保护。要显示它您需要在浏览器中启用JavaScript。 (A.S.K.), 该Email地址已收到反垃圾邮件插件保护。要显示它您需要在浏览器中启用JavaScript。 (N.B.)

https://doi.org/10.1016/j.cmet.2020.04.001

Biological aging involves an interplay of conserved and targetable molecular mechanisms, summarized as the hallmarks of aging. Metformin, a biguanide that combats age-related disorders and improves health span, is the first drug to be tested for its age-targeting effects in the large clinical trial—TAME (targeting aging by metformin). This review focuses on metformin’s mechanisms in attenuating hallmarks of aging and their interconnectivity, by improving nutrient sensing, enhancing autophagy and intercellular communication, protecting against macromolecular damage, delaying stem cell aging, modulating mitochondrial function, regulating transcription, and lowering telomere attrition and senescence. These characteristics make metformin an attractive gerotherapeutic to translate to human trials.

MicroRNA-455-3p improves synaptic, cognitive functions and extends lifespan: Relevance to Alzheimer’s disease

Subodh Kumar a,**, Hallie Morton a , Neha Sawant a , Erika Orlov a , Lloyd E Bunquin a , Jangampalli Adi Pradeepkiran a , Razelle Alvir a , P. Hemachandra Reddy a , b ,c,d,e,

a Internal Medicine Department, Texas Tech University Health Sciences Center, Lubbock, TX, USA

b Neuroscience & Pharmacology, Texas Tech University Health Sciences Center, Lubbock, TX, USA

c Neurology Departments School of Medicine, Texas Tech University Health Sciences Center, Lubbock, TX, USA

d Public Health Department of Graduate School of Biomedical Sciences, Texas Tech University Health Sciences Center, Lubbock, TX, USA

e Department of Speech, Language and Hearing Sciences, School Health Professions, Texas Tech University Health Sciences Center, Lubbock, TX, USA

ARTICLE INFO

Keywords: Alzheimer’s disease     MicroRNA-455-3p   Mouse models   Mitochondrial biogenesis   Synaptic activity

ABSTRACT

Background: MicroRNA-455-3p is one of the highly conserved miRNAs involved in multiple cellular functions in humans and we explored its relevance to learning and memory functions in Alzheimer’s disease (AD). Our recent in vitro studies exhibited the protective role of miR-455-3p against AD toxicities in reducing full-length APP and amyloid-β (Aβ) levels, and also in reducing defective mitochondrial biogenesis, impaired mitochondrial dynamics and synaptic deficiencies. In the current study, we sought to determine the function of miR-455-3p in mouse models. 

Methods: For the first time we generated both transgenic (TG) and knockout (KO) mouse models of miR-455-3p. We determined the lifespan extension, cognitive function, mitochondrial biogenesis, mitochondrial dynamics, mitochondrial morphology, dendritic spine density, synapse numbers and synaptic activity in miR-455-3p TG and KO mice.

Results: MiR-455-3p TG mice lived 5 months longer than wild-type (WT) counterparts, whereas KO mice lived 4 months shorter than WT mice. Morris water maze test showed improved cognitive behavior, spatial learning and memory in miR-455-3p TG mice relative to age-matched WT mice and miR-455-3p KO mice. Further, mitochondrial biogenesis, dynamics and synaptic activities were enhanced in miR-455-3p TG mice, while these were reduced in KO mice. Overall, overexpressed miR-455-3p in mice displayed protective effects, whereas depleted miR-455-3p in mice exhibited deleterious effects in relation to lifespan, cognitive behavior, and mitochondrial and synaptic activities.

Conclusion: Both mouse models could be ideal research tools to understand the molecular basis of aging and its relevance to AD and other age-related diseases.

* Corresponding author. Internal Medicine, Cell Biology & Biochemistry, Neuroscience & Pharmacology, Neurology, Public Health and School of Health Professions, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX, 79430, United States.

** Corresponding author. Internal Medicine Department, Texas Tech University Health Sciences Center, 3601 4th Street, Lubbock, TX, 79430, United States. E-mail addresses: 该Email地址已收到反垃圾邮件插件保护。要显示它您需要在浏览器中启用JavaScript。 (S. Kumar), 该Email地址已收到反垃圾邮件插件保护。要显示它您需要在浏览器中启用JavaScript。 (P.H. Reddy).

https://doi.org/10.1016/j.redox.2021.102182

Received 14 October 2021; Received in revised form 2 November 2021; Accepted 6 November 2021

Available online 9 November 2021

2213-2317/© 2021 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Fisetin is a senotherapeutic that extends health and lifespan

Matthew J. Yousefzadeh a,1 , Yi Zhu b,1 , Sara J. McGowan a,1 , Luise Angelini a,1 , Heike Fuhrmann-Stroissnigg a ,Ming Xu b , Yuan Yuan Ling a , Kendra I. Melos a , Tamar Pirtskhalava b , Christina L. Inman b , Collin McGuckian a ,Erin A. Wade a , Jonathon I. Kato a , Diego Grassi a , Mark Wentworth c , Christin E. Burd d , Edgar A. Arriaga e ,Warren L. Ladiges f , Tamara Tchkonia b , James L. Kirkland b , Paul D. Robbins a, ⁎, Laura J. Niedernhofer a, ⁎

a Department of Molecular Medicine and the Center on Aging, The Scripps Research Institute, 130 Scripps Way, Jupiter, FL 33458, United States

b Robert and Arlene Kogod Center on Aging, Mayo Clinic, 200 First St., S.W., Rochester, MN 55905, United States

c Office of Research Regulatory Support, Mayo Clinic, Rochester, MN 55905, United States

d Department of Molecular Genetics and Cancer Biology and Genetics, The Ohio State University, Columbus, OH 43210, United States

e Department of Chemistry, University of Minnesota, Minneapolis, MN 55455-0431, United States

f Department of Comparative Medicine, University of Washington, Seattle, WA 98195, United States

article info

Article history:

Received 11 July 2018

Received in revised form 30 August 2018

Accepted 10 September 2018

Available online 29 September 2018

Keywords: Senolytic  Aging  Progeria  Healthspan  Lifespan  Senescence

⁎ Corresponding author at: Institute on the Biology of Aging and Metabolism, Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota Medical School, 6-155 Jackson Hall, 321 Church Street, SE, Minneapolis, MN 55455, United States. E-mail addresses: 该Email地址已收到反垃圾邮件插件保护。要显示它您需要在浏览器中启用JavaScript。 (P.D. Robbins), 该Email地址已收到反垃圾邮件插件保护。要显示它您需要在浏览器中启用JavaScript。 (L.J. Niedernhofer). 1 Contributed equally.

abstract

Background: Senescence is a tumor suppressor mechanism activated in stressed cells to prevent replication of damaged DNA. Senescent cells have been demonstrated to play a causal role in driving aging and age-related diseases using genetic and pharmacologic approaches. We previously demonstrated that the combination of dasatinib and the flavonoid quercetin is a potent senolytic improving numerous age-related conditions including frailty, osteoporosis and cardiovascular disease. The goal of this study was to identify flavonoids with more potent senolytic activity.

Methods: A panel of flavonoid polyphenols was screened for senolytic activity using senescent murine and human fibroblasts, driven by oxidative and genotoxic stress, respectively. The top senotherapeutic flavonoid was tested in mice modeling a progeroid syndrome carrying a p16INK4a-luciferase reporter and aged wild-type mice to determine the effects of fisetin on senescence markers, age-related histopathology, disease markers, health span and lifespan. Human adipose tissue explants were used to determine if results translated.

Findings: Of the 10 flavonoids tested, fisetin was the most potent senolytic. Acute or intermittent treatment of progeroid and old mice with fisetin reduced senescence markers in multiple tissues, consistent with a hit-and run senolytic mechanism. Fisetin reduced senescence in a subset of cells in murine and human adipose tissue, demonstrating cell-type specificity. Administration of fisetin to wild-type mice late in life restored tissue homeostasis, reduced age-related pathology, and extended median and maximum lifespan.

Interpretation: The natural product fisetin has senotherapeutic activity in mice and in human tissues. Late life intervention was sufficient to yield a potent health benefit. These characteristics suggest the feasibility to translation to human clinical studies.

Fund: NIH grants P01 AG043376 (PDR, LJN), U19 AG056278 (PDR, LJN, WLL), R24 AG047115 (WLL), R37 AG013925 (JLK), R21 AG047984 (JLK), P30 DK050456 (Adipocyte Subcore, JLK), a Glenn Foundation/American Federation for Aging Research (AFAR) BIG Award (JLK), Glenn/AFAR (LJN, CEB), the Ted Nash Long Life and Noaber Foundations (JLK), the Connor Group (JLK), Robert J. and Theresa W. Ryan (JLK), and a Minnesota Partnership Grant (AMAY-UMN#99)-P004610401–1 (JLK, EAA).

© 2018 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license

(http://creativecommons.org/licenses/by-nc-nd/4.0/).

Research in Context

Evidence before this study

      Pharmacological targeting of fundamental mechanisms of aging has the ability to reduce the severity or delay the onset of multiple age-associated co-morbidities simultaneously. One key mechanism demonstrated to drive aging is cellular senescence, whereby accumulation of DNA damage and/or other cellular stressors cause proliferating or terminally differentiated non-dividing cells to enter a state characterized by profound chromatin and secretome changes, increased expression of the cell cycle inhibitor p16Ink4a in many but not all senescent cells, replicative arrest, and resistance to apoptosis. Senescent cells can develop a senescence-associated secretory phenotype (SASP), which has deleterious paracrine and systemic effects. Senescent cells are rare in young individuals, but increase with age in multiple tissues. Drugs able to selectively kill senescent cells, termed senolytics, have been identified including the combination of dastinib and quercetin (D ± Q), which improves many aspects of aging in mouse models of accelerated and natural aging. However, safer and improved drugs targeting senescence likely are needed to eliminate senescent cells safely from multiple organs or even within a single tissue.

Added value of the study

      This study identifies the flavonoid polyphenol fisetin as having greater senotherapeutic activity in cultured cells than quercetin. In addition, fisetin had potent senotherapeutic activity in vivo. Treatment of progeroid and aged wild-type mice acutely or intermittently with fisetin reduced senescence markers in multiple tissues and a subset of cell types in adipose tissue. Importantly, chronic administration of fisetin to wild-type mice late in life improved tissue homeostasis, suppressed age-related pathology, and extended median and maximum lifespan. This result, similar to a recent report on the combination of D ± Q, is the first to document extension of both health span and lifespan by a senolytic with few side effects, even though administration was started late in life.

Implications of all the available evidence

      Taken together, these data establish the natural product fisetin as a potent senotherapeutic, able to reduce the burden of senescent T, NK, progenitor, and endothelial cells from fat tissue, and demonstrate that reducing the senescent cell burden in mice even late in life is sufficient to have a significant health impact. Given the known safety profile of fisetin in humans, clinical trials are beginning in order to test if fisetin can be used effectively to reduce senescent cell burden and alleviate dysfunction in elderly subjects.

Progeria: A Paradigm for Translational Medicine

Leslie B. Gordon,1,2, * Frank G. Rothman,3 Carlos Lo´pez-Otı´n,4 and Tom Misteli5, *

1 Department of Anesthesia, Boston Children’s Hospital and Harvard Medical School, Boston, MA 02115, USA

2 Department of Pediatrics, Hasbro Children’s Hospital and Warren Alpert Medical School of Brown University, Providence, RI 02912, USA

3 Division of Biology and Medicine, Brown University, Providence, RI 02912, USA

4 Departamento de Bioquı´mica y Biologı´a Molecular, Instituto Universitario de Oncologı´a (IUOPA), Universidad de Oviedo, 33006 Oviedo, Spain

5National Cancer Institute, NIH, Bethesda, MD 20892, USA

*Correspondence: 该Email地址已收到反垃圾邮件插件保护。要显示它您需要在浏览器中启用JavaScript。 (L.B.G.), 该Email地址已收到反垃圾邮件插件保护。要显示它您需要在浏览器中启用JavaScript。 (T.M.)

http://dx.doi.org/10.1016/j.cell.2013.12.028

Rare diseases are powerful windows into biological processes and can serve as models for the development of therapeutic strategies. The progress made on the premature aging disorder Progeria is a shining example of the impact that studies of rare diseases can have.

A phase 2/3 randomized clinical trial followed by an open-label extension to evaluate the effectiveness of elamipretide in Barth syndrome, a genetic disorder of mitochondrial cardiolipin metabolism

W. Reid Thompson, MD1 , Brittany Hornby, PT, DPT2 , Ryan Manuel, BS3 , Elena Bradley, PT, DPT2 , Janice Laux, PT2 , Jim Carr, PharmD4 and Hilary J. Vernon, MD, PhD 3

Purpose: To evaluate effectiveness of elamipretide in Barth syndrome (BTHS), a genetic condition of defects in TAZ, which causes abnormal cardiolipin on the inner mitochondrial

Methods: We performed a randomized, double-blind, placebocontrolled crossover trial followed by an open-label extension in BTHS to test the effect of elamipretide, a mitochondrial tetrapeptide that interacts with cardiolipin. In part 1, 12 subjects were randomized to 40 mg per day of elamipretide or placebo for 12 weeks, followed by a 4-week washout and then 12 weeks on the opposite arm. Ten subjects continued on the open-label extension (part 2) of 40 mg per day of elamipretide, with eight subjects reaching 36 weeks. Primary endpoints were improvement on the 6-minute walk test (6MWT) and improvement on a BTHS Symptom Assessment (BTHS-SA) scale.

Results: In part 1 neither primary endpoint was met. At 36 weeks in part 2, there were significant improvements in 6MWT (+95.9 m, p = 0.024) and BTHS-SA (-2.1 points, p = 0.031). There were also significant improvements in secondary endpoints including knee extensor strength, patient global impression of symptoms, and some cardiac parameters. Conclusion: In this interventional clinical trial in BTHS, daily administration of elamipretide led to improvement in BTHS

Genetics in Medicine (2021) 23:471–478; https://doi.org/10.1038/s41436- 020-01006-8

Keywords: Barth syndrome; elamipretide; cardiolipin; 6-minute walk test

1 Department of Pediatric Cardiology, Johns Hopkins University School of Medicine, Baltimore, MD, USA;

2 Department of Physical Therapy, Kennedy Krieger Institute, Baltimore, MD, USA;

3 Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA; 4 Stealth BioTherapeutics Inc, Newton, MA, USA.

Correspondence: Hilary J. Vernon (该Email地址已收到反垃圾邮件插件保护。要显示它您需要在浏览器中启用JavaScript。)

These authors contributed equally: W. Reid Thompson, Brittany Hornby

Submitted 11 August 2020; revised 29 September 2020; accepted: 1 October 2020

Published online: 20 October 2020

Pathogenic Mechanisms of Somatic Mutation and Genome Mosaicism in Aging

Jan Vijg1,2,* and Xiao Dong1 1Department of Genetics, Albert Einstein College of Medicine, New York, NY 10461, USA 2Center for Single-Cell Omics, School of Public Health, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China *Correspondence: 该Email地址已收到反垃圾邮件插件保护。要显示它您需要在浏览器中启用JavaScript。 https://doi.org/10.1016/j.cell.2020.06.024

Age-related accumulation of postzygotic DNA mutations results in tissue genetic heterogeneity known as somatic mosaicism. Although implicated in aging as early as the 1950s, somatic mutations in normal tissue have been difficult to study because of their low allele fractions. With the recent emergence of cost-effective highthroughput sequencing down to the single-cell level, enormous progress has been made in our capability to quantitatively analyze somatic mutations in human tissue in relation to aging and disease. Here we first review how recent technological progress has opened up this field, providing the first broad sets of quantitative information on somatic mutations in vivo necessary to gain insight into their possible causal role in human aging and disease. We then propose three major mechanisms that can lead from accumulated de novo mutations across tissues to cell functional loss and human disease.