Research Paper Volume 8, Issue 3 pp 484—505
MicroRNA-15b regulates mitochondrial ROS production and the senescence-associated secretory phenotype through sirtuin 4/SIRT4
- 1 Institut für Biochemie und Molekularbiologie II, Universitätsklinikum der Heinrich-Heine-Universität, Düsseldorf, Germany
- 2 IUF – Leibniz Research Institute for Environmental Medicine, Düsseldorf, Germany
- 3 Institut für Transplantationsdiagnostik und Zelltherapeutika (ITZ), Düsseldorf, Germany
- 4 Biologisch-Medizinisches Forschungszentrum (BMFZ), Düsseldorf, Germany
- 5 Molecular Proteomics Laboratory, BMFZ, Universitätsklinikum der Heinrich-Heine-Universität, Düsseldorf, Germany
- 6 University of Düsseldorf, Medical Faculty, Düsseldorf, Germany
Received: August 5, 2015 Accepted: January 30, 2016 Published: February 26, 2016
https://doi.org/10.18632/aging.100905How to Cite
Abstract
Mammalian sirtuins are involved in the control of metabolism and life-span regulation. Here, we link the mitochondrial sirtuin SIRT4 with cellular senescence, skin aging, and mitochondrial dysfunction. SIRT4 expression significantly increased in human dermal fibroblasts undergoing replicative or stress-induced senescence triggered by UVB or gamma-irradiation. In-vivo, SIRT4 mRNA levels were upregulated in photoaged vs. non-photoaged human skin. Interestingly, in all models of cellular senescence and in photoaged skin, upregulation of SIRT4 expression was associated with decreased levels of miR-15b. The latter was causally linked to increased SIRT4 expression because miR-15b targets a functional binding site in the SIRT4 gene and transfection of oligonucleotides mimicking miR-15b function prevented SIRT4 upregulation in senescent cells. Importantly, increased SIRT4 negatively impacted on mitochondrial functions and contributed to the development of a senescent phenotype. Accordingly, we observed that inhibition of miR-15b, in a SIRT4-dependent manner, increased generation of mitochondrial reactive oxygen species, decreased mitochondrial membrane potential, and modulated mRNA levels of nuclear encoded mitochondrial genes and components of the senescence-associated secretory phenotype (SASP). Thus, miR-15b is a negative regulator of stress-induced SIRT4 expression thereby counteracting senescence associated mitochondrial dysfunction and regulating the SASP and possibly organ aging, such as photoaging of human skin.
Abbreviations
CytC: cytochrom C; γIR: gamma-irradiation; GDH: glutamate dehydrogenase; miRNA: microRNA; mitoQ: 10-(6′-ubiquinonyl) decyltriphenylphosphonium bromide; MMP1: matrix metalloproteinase-1; MTCO2: mitochondrially encoded cytochrome C oxidase II; mtSIRT: mitochondrially localized sirtuin; NRF1: nuclear respiratory factor 1; PDH: pyruvate dehydrogenase; qRT-PCR: quantitative real-time PCR; ROS: reactive oxygen species; SASP: senescence associated secretory phenotype; SIRT: sirtuin; TACC3: Transforming Acidic Coiled Coil 3; TFAM: transcription factor A; UTR: untranslated region; UV: ultraviolet; VEGF: vascular endothelial growth factor.