Nirmala Hariharan1, Pearl Quijada1, Sadia Mohsin1, Anya Joyo1, Kaitlen Samse1, Megan Monsanto1, Andrea De La Torre1, Daniele Avitabile2, Lucia Ormachea1, Michael J McGregor1, Emily J Tsai3, Mark A Sussman4. 1. Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, California. 2. Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, California; Department of Clinical and Molecular Medicine, "Sapienza" University of Rome, Rome, Italy. 3. Section in Cardiology and Cardiovascular Research Center, Temple University School of Medicine, Philadelphia, Pennsylvania. 4. Department of Biology, San Diego State University Heart Institute, San Diego State University, San Diego, California. Electronic address: heartman4ever@icloud.com.
Abstract
BACKGROUND: Functional decline in stem cell-mediated regeneration contributes to aging associated with cellular senescence in c-kit+ cardiac progenitor cells (CPCs). Clinical implementation of CPC-based therapy in elderly patients would benefit tremendously from understanding molecular characteristics of senescence to antagonize aging. Nucleostemin (NS) is a nucleolar protein regulating stem cell proliferation and pluripotency. OBJECTIVES: This study sought to demonstrate that NS preserves characteristics associated with "stemness" in CPCs and antagonizes myocardial senescence and aging. METHODS: CPCs isolated from human fetal (fetal human cardiac progenitor cell [FhCPC]) and adult failing (adult human cardiac progenitor cell [AhCPC]) hearts, as well as young (young cardiac progenitor cell [YCPC]) and old mice (old cardiac progenitor cell [OCPC]), were studied for senescence characteristics and NS expression. Heterozygous knockout mice with 1 functional allele of NS (NS+/-) were used to demonstrate that NS preserves myocardial structure and function and slows characteristics of aging. RESULTS: NS expression is decreased in AhCPCs relative to FhCPCs, correlating with lowered proliferation potential and shortened telomere length. AhCPC characteristics resemble those of OCPCs, which have a phenotype induced by NS silencing, resulting in cell flattening, senescence, multinucleated cells, decreased S-phase progression, diminished expression of stemness markers, and up-regulation of p53 and p16. CPC senescence resulting from NS loss is partially p53 dependent and is rescued by concurrent silencing of p53. Mechanistically, NS induction correlates with Pim-1 kinase-mediated stabilization of c-Myc. Engineering OCPCs and AhCPCs to overexpress NS decreases senescent and multinucleated cells, restores morphology, and antagonizes senescence, thereby preserving phenotypic properties of "stemness." Early cardiac aging with a decline in cardiac function, an increase in senescence markers p53 and p16, telomere attrition, and accompanied CPC exhaustion is evident in NS+/- mice. CONCLUSIONS: Youthful properties and antagonism of senescence in CPCs and the myocardium are consistent with a role for NS downstream from Pim-1 signaling that enhances cardiac regeneration.
BACKGROUND: Functional decline in stem cell-mediated regeneration contributes to aging associated with cellular senescence in c-kit+ cardiac progenitor cells (CPCs). Clinical implementation of CPC-based therapy in elderly patients would benefit tremendously from understanding molecular characteristics of senescence to antagonize aging. Nucleostemin (NS) is a nucleolar protein regulating stem cell proliferation and pluripotency. OBJECTIVES: This study sought to demonstrate that NS preserves characteristics associated with "stemness" in CPCs and antagonizes myocardial senescence and aging. METHODS:CPCs isolated from human fetal (fetal human cardiac progenitor cell [FhCPC]) and adult failing (adult human cardiac progenitor cell [AhCPC]) hearts, as well as young (young cardiac progenitor cell [YCPC]) and old mice (old cardiac progenitor cell [OCPC]), were studied for senescence characteristics and NS expression. Heterozygous knockout mice with 1 functional allele of NS (NS+/-) were used to demonstrate that NS preserves myocardial structure and function and slows characteristics of aging. RESULTS:NS expression is decreased in AhCPCs relative to FhCPCs, correlating with lowered proliferation potential and shortened telomere length. AhCPC characteristics resemble those of OCPCs, which have a phenotype induced by NS silencing, resulting in cell flattening, senescence, multinucleated cells, decreased S-phase progression, diminished expression of stemness markers, and up-regulation of p53 and p16. CPC senescence resulting from NS loss is partially p53 dependent and is rescued by concurrent silencing of p53. Mechanistically, NS induction correlates with Pim-1 kinase-mediated stabilization of c-Myc. Engineering OCPCs and AhCPCs to overexpress NS decreases senescent and multinucleated cells, restores morphology, and antagonizes senescence, thereby preserving phenotypic properties of "stemness." Early cardiac aging with a decline in cardiac function, an increase in senescence markers p53 and p16, telomere attrition, and accompanied CPC exhaustion is evident in NS+/- mice. CONCLUSIONS: Youthful properties and antagonism of senescence in CPCs and the myocardium are consistent with a role for NS downstream from Pim-1 signaling that enhances cardiac regeneration.
Authors: Fabrizio d'Adda di Fagagna; Philip M Reaper; Lorena Clay-Farrace; Heike Fiegler; Philippa Carr; Thomas Von Zglinicki; Gabriele Saretzki; Nigel P Carter; Stephen P Jackson Journal: Nature Date: 2003-11-05 Impact factor: 49.962
Authors: Chantal Beekman; Massimo Nichane; Sarah De Clercq; Marion Maetens; Thomas Floss; Wolfgang Wurst; Eric Bellefroid; Jean-Christophe Marine Journal: Mol Cell Biol Date: 2006-09-25 Impact factor: 4.272
Authors: Collin Matsumoto; Yan Jiang; Jacqueline Emathinger; Pearl Quijada; Nathalie Nguyen; Andrea De La Torre; Maryam Moshref; Jonathan Nguyen; Aimee B Levinson; Minyoung Shin; Mark A Sussman; Nirmala Hariharan Journal: Stem Cells Date: 2018-02-25 Impact factor: 6.277
Authors: Pearl Quijada; Nirmala Hariharan; Jonathan D Cubillo; Kristin M Bala; Jacqueline M Emathinger; Bingyan J Wang; Lucia Ormachea; Donald M Bers; Mark A Sussman; Coralie Poizat Journal: J Biol Chem Date: 2015-08-31 Impact factor: 5.157