1
|
Cavinato M, Martic I, Wedel S, Pittl A, Koziel R, Weinmmüllner R, Schosserer M, Jenewein B, Bobbili MR, Arcalis E, Haybaeck J, Pierer G, Ploner C, Hermann M, Romani N, Schmuth M, Grillari J, Jansen-Dürr P. Elimination of damaged mitochondria during UVB-induced senescence is orchestrated by NIX-dependent mitophagy. Aging Cell 2024; 23:e14186. [PMID: 38761001 DOI: 10.1111/acel.14186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 04/12/2024] [Accepted: 04/17/2024] [Indexed: 05/20/2024] Open
Abstract
Skin aging is the result of two types of aging, "intrinsic aging" an inevitable consequence of physiologic and genetically determined changes and "extrinsic aging," which is dependent on external factors such as exposure to sunlight, smoking, and dietary habits. UVB causes skin injury through the generation of free radicals and other oxidative byproducts, also contributing to DNA damage. Appearance and accumulation of senescent cells in the skin are considered one of the hallmarks of aging in this tissue. Mitochondria play an important role for the development of cellular senescence, in particular stress-induced senescence of human cells. However, many aspects of mitochondrial physiology relevant to cellular senescence and extrinsic skin aging remain to be unraveled. Here, we demonstrate that mitochondria damaged by UVB irradiation of human dermal fibroblasts (HDF) are eliminated by NIX-dependent mitophagy and that this process is important for cell survival under these conditions. Additionally, UVB-irradiation of human dermal fibroblasts (HDF) induces the shedding of extracellular vesicles (EVs), and this process is significantly enhanced in UVB-irradiated NIX-depleted cells. Our findings establish NIX as the main mitophagy receptor in the process of UVB-induced senescence and suggest the release of EVs as an alternative mechanism of mitochondrial quality control in HDF.
Collapse
Affiliation(s)
- Maria Cavinato
- Institute for Biomedical Aging Research, University of Innsbruck, Innsbruck, Austria
- Center for Molecular Biosciences Innsbruck (CMBI), Innsbruck, Austria
| | - Ines Martic
- Institute for Biomedical Aging Research, University of Innsbruck, Innsbruck, Austria
- Center for Molecular Biosciences Innsbruck (CMBI), Innsbruck, Austria
| | - Sophia Wedel
- Institute for Biomedical Aging Research, University of Innsbruck, Innsbruck, Austria
- Center for Molecular Biosciences Innsbruck (CMBI), Innsbruck, Austria
| | - Annabella Pittl
- Institute for Biomedical Aging Research, University of Innsbruck, Innsbruck, Austria
- Center for Molecular Biosciences Innsbruck (CMBI), Innsbruck, Austria
| | - Rafal Koziel
- Institute for Biomedical Aging Research, University of Innsbruck, Innsbruck, Austria
| | - Regina Weinmmüllner
- Institute of Molecular Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Markus Schosserer
- Institute of Medical Genetics, Center for Pathobiochemistry and Genetics, Medical University Vienna, Vienna, Austria
- Austrian Cluster for Tissue Regeneration, Vienna, Austria
| | - Brigitte Jenewein
- Institute for Biomedical Aging Research, University of Innsbruck, Innsbruck, Austria
- Center for Molecular Biosciences Innsbruck (CMBI), Innsbruck, Austria
| | - Madhusudhan Reddy Bobbili
- Institute of Molecular Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
- Austrian Cluster for Tissue Regeneration, Vienna, Austria
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, Vienna, Austria
| | - Elsa Arcalis
- Institut für Pflanzenbiotechnologie und Zellbiologie, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria
| | - Johannes Haybaeck
- Institute of Pathology, Neuropathology and Molecular Pathology, Medical University of Innsbruck, Innsbruck, Austria
- Department of Pathology, Saint Vincent Hospital Zams, Zams, Austria
- Department of Pathology, Labor Team, Goldach, Switzerland
| | - Gerhard Pierer
- Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Innsbruck, Innsbruck, Austria
| | - Christian Ploner
- Department of Plastic, Reconstructive and Aesthetic Surgery, Medical University of Innsbruck, Innsbruck, Austria
| | - Martin Hermann
- Department of Anesthesiology and Critical Care Medicine, Medical University of Innsbruck, Innsbruck, Austria
| | - Nikolaus Romani
- Department of Dermatology, Venereology and Allergology, Medical University of Innsbruck, Innsbruck, Austria
| | - Matthias Schmuth
- Department of Dermatology, Venereology and Allergology, Medical University of Innsbruck, Innsbruck, Austria
| | - Johannes Grillari
- Institute of Molecular Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
- Austrian Cluster for Tissue Regeneration, Vienna, Austria
- Ludwig Boltzmann Institute for Traumatology, The Research Center in Cooperation with AUVA, Vienna, Austria
| | - Pidder Jansen-Dürr
- Institute for Biomedical Aging Research, University of Innsbruck, Innsbruck, Austria
- Center for Molecular Biosciences Innsbruck (CMBI), Innsbruck, Austria
| |
Collapse
|
2
|
Differential angiogenesis of bone and muscle endothelium in aging and inflammatory processes. Commun Biol 2023; 6:126. [PMID: 36721025 PMCID: PMC9889796 DOI: 10.1038/s42003-023-04515-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 01/20/2023] [Indexed: 02/01/2023] Open
Abstract
Different tissues have different endothelial features, however, the implications of this heterogeneity in pathological responses are not clear yet. "Inflamm-aging" has been hypothesized as a possible trigger of diseases, including osteoarthritis (OA) and sarcopenia, often present in the same patient. To highlight a possible contribution of organ-specific endothelial cells (ECs), we compare ECs derived from bone and skeletal muscle of the same OA patients. OA bone ECs show a pro-inflammatory signature and higher angiogenic sprouting as compared to muscle ECs, in control conditions and stimulated with TNFα. Furthermore, growth of muscle but not bone ECs decreases with increasing patient age and systemic inflammation. Overall, our data demonstrate that inflammatory conditions in OA patients differently affect bone and muscle ECs, suggesting that inflammatory processes increase angiogenesis in subchondral bone while associated systemic low-grade inflammation impairs angiogenesis in muscle, possibly highlighting a vascular trigger linking OA and sarcopenia.
Collapse
|
3
|
Ushakov RE, Aksenov ND, Pugovkina NA, Burova EB. Effects of IGFBP3 knockdown on human endometrial mesenchymal stromal cells stress-induced senescence. Biochem Biophys Res Commun 2021; 570:143-147. [PMID: 34284139 DOI: 10.1016/j.bbrc.2021.07.046] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 07/13/2021] [Indexed: 01/10/2023]
Abstract
Insulin-like growth factor binding protein 3 (IGFBP3) is known for its pleiotropic ability to regulate various cellular processes such as proliferation, apoptosis, differentiation etc. It has recently been shown that IGFBP3 is part of the secretome of senescent human endometrial mesenchymal stromal cells (MESCs) (Griukova et al., 2019) that takes part in paracrine propagation of senescence-like phenotype in MESCs (Vassilieva et al., 2020); however, mechanisms of pro-senescent IGFBP3 action in MESCs remain still unexplored. This study is aimed at elucidating the role of IGFBP3 upregulation in senescent MESCs. IGFBP3 knockdown in MESCs committed to H2O2-induced senescence led to partial abrogation of p21/Rb axis, to elevated ERK phosphorylation and to increase in SA-β-gal activity. Additionally, MESCs derived from various donors were found to demonstrate different IGFBP3 regulation during stress-induced senescence. Obtained results suggest ambiguous role of IGFBP3 in stress-induced senescence of MESCs.
Collapse
Affiliation(s)
- Roman E Ushakov
- Institute of Cytology RAS, Tikhoretsky Ave 4, St. Petersburg, 194064, Russia
| | - Nikolay D Aksenov
- Institute of Cytology RAS, Tikhoretsky Ave 4, St. Petersburg, 194064, Russia
| | - Natalia A Pugovkina
- Institute of Cytology RAS, Tikhoretsky Ave 4, St. Petersburg, 194064, Russia
| | - Elena B Burova
- Institute of Cytology RAS, Tikhoretsky Ave 4, St. Petersburg, 194064, Russia.
| |
Collapse
|
4
|
Saccà SC, Vernazza S, Iorio EL, Tirendi S, Bassi AM, Gandolfi S, Izzotti A. Molecular changes in glaucomatous trabecular meshwork. Correlations with retinal ganglion cell death and novel strategies for neuroprotection. PROGRESS IN BRAIN RESEARCH 2020; 256:151-188. [PMID: 32958211 DOI: 10.1016/bs.pbr.2020.06.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Glaucoma is a chronic neurodegenerative disease characterized by retinal ganglion cell loss. Although significant advances in ophthalmologic knowledge and practice have been made, some glaucoma mechanisms are not yet understood, therefore, up to now there is no effective treatment able to ensure healing. Indeed, either pharmacological or surgical approaches to this disease aim in lowering intraocular pressure, which is considered the only modifiable risk factor. However, it is well known that several factors and metabolites are equally (if not more) involved in glaucoma. Oxidative stress, for instance, plays a pivotal role in both glaucoma onset and progression because it is responsible for the trabecular meshwork cell damage and, consequently, for intraocular pressure increase as well as for glaucomatous damage cascade. This review at first shows accurately the molecular-derived dysfunctions in antioxidant system and in mitochondria homeostasis which due to both oxidative stress and aging, lead to a chronic inflammation state, the trabecular meshwork damage as well as the glaucoma neurodegeneration. Therefore, the main molecular events triggered by oxidative stress up to the proapoptotic signals that promote the ganglion cell death have been highlighted. The second part of this review, instead, describes some of neuroprotective agents such as polyphenols or polyunsaturated fatty acids as possible therapeutic source against the propagation of glaucomatous damage.
Collapse
Affiliation(s)
- Sergio C Saccà
- Policlinico San Martino University Hospital, Department of Neuroscience and sense organs, Ophthalmology Unit, Genoa, Italy.
| | | | | | - Sara Tirendi
- Department of Experimental Medicine (DIMES), University of Genoa, Genoa, Italy; Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), Pisa, Italy
| | - Anna Maria Bassi
- Department of Experimental Medicine (DIMES), University of Genoa, Genoa, Italy; Inter-University Center for the Promotion of the 3Rs Principles in Teaching & Research (Centro 3R), Pisa, Italy
| | - Stefano Gandolfi
- Ophthalmology Unit, Department of Biological, Biotechnological and Translational Sciences, University of Parma, Parma, Italy
| | - Alberto Izzotti
- Department of Experimental Medicine (DIMES), University of Genoa, Genoa, Italy; Mutagenesis Unit, IRCCS Ospedale Policlinico San Martino, Genoa, Italy
| |
Collapse
|
5
|
Ji J, Hao Z, Liu H, Liu Y, Liu J, Lin B, Ma C, Lin Y. Effect of KNDC1 overexpression on the senescence of human umbilical vein endothelial cells. Mol Med Rep 2018; 17:7037-7044. [PMID: 29568929 PMCID: PMC5928657 DOI: 10.3892/mmr.2018.8775] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 02/01/2018] [Indexed: 12/15/2022] Open
Abstract
Kinase non-catalytic C-lobe domain containing 1 (KNDC1) exists in dendrites, guanine nucleotide exchange factor complexes and neuronal cell bodies as a putative protein-protein interaction module that regulates a number of signaling pathways. Previous studies have demonstrated that the knockdown of KNDC1 delays human umbilical vein endothelial cell (HUVEC) senescence. However, the effect of KNDC1 overexpression on HUVEC function remains unclear. In the present study, an adenovirus vector carrying KNDC1 was constructed and then transfected into endothelial cells to observe cell senescence. Furthermore, the effect of KNDC1 overexpression on HUVEC senescence was investigated in vitro and the underlying molecular mechanism was investigated. Senescence-associated β-galactosidase staining was used to determine cellular senescence and reactive oxygen species (ROS) were monitored to detect the level of cell oxidative stress. The mRNA transcription level and protein expression were analyzed by reverse transcription-quantitative polymerase chain reaction and western blot analysis, respectively. The results demonstrated that KNDC1 overexpression possibly inhibited HUVEC activity and function and promoted HUVEC senescence. Mechanistic studies demonstrated that KNDC1 triggered a p53-ROS positive feedback loop, which serves a crucial role in regulating senescence. In conclusion, to the best of the authors' knowledge, this is the first time that KNDC1-adenovirus vector inhibition of HUVEC proliferation by activating the p53 signaling pathway has been reported. Theoretically, the results of the present study also support KNDC1 as a therapeutic target for future anti-senescence.
Collapse
Affiliation(s)
- Jinrui Ji
- Department of Cardiology, Zhengzhou People Hospital, Southern Medical University, Zhengzhou, Henan 450002, P.R. China
| | - Zhenxuan Hao
- Department of Cardiology, Zhengzhou People Hospital, Southern Medical University, Zhengzhou, Henan 450002, P.R. China
| | - Hengliang Liu
- Department of Cardiology, Zhengzhou People Hospital, Southern Medical University, Zhengzhou, Henan 450002, P.R. China
| | - Yang Liu
- Department of Cardiology, Zhengzhou People Hospital, Southern Medical University, Zhengzhou, Henan 450002, P.R. China
| | - Jing Liu
- Department of Cardiology, Zhengzhou People Hospital, Southern Medical University, Zhengzhou, Henan 450002, P.R. China
| | - Binghui Lin
- Department of Cardiology, Zhengzhou People Hospital, Southern Medical University, Zhengzhou, Henan 450002, P.R. China
| | - Chao Ma
- Department of Cardiology, Zhengzhou People Hospital, Southern Medical University, Zhengzhou, Henan 450002, P.R. China
| | - Yajun Lin
- The MOH Key Laboratory of Geriatrics, Beijing Hospital, National Center of Gerontology, Beijing 100730, P.R. China
| |
Collapse
|
6
|
Chen M, Lyu G, Han M, Nie H, Shen T, Chen W, Niu Y, Song Y, Li X, Li H, Chen X, Wang Z, Xia Z, Li W, Tian XL, Ding C, Gu J, Zheng Y, Liu X, Hu J, Wei G, Tao W, Ni T. 3' UTR lengthening as a novel mechanism in regulating cellular senescence. Genome Res 2018; 28:285-294. [PMID: 29440281 PMCID: PMC5848608 DOI: 10.1101/gr.224451.117] [Citation(s) in RCA: 70] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2017] [Accepted: 01/24/2018] [Indexed: 01/09/2023]
Abstract
Cellular senescence has been viewed as a tumor suppression mechanism and also as a contributor to individual aging. Widespread shortening of 3' untranslated regions (3' UTRs) in messenger RNAs (mRNAs) by alternative polyadenylation (APA) has recently been discovered in cancer cells. However, the role of APA in the process of cellular senescence remains elusive. Here, we found that hundreds of genes in senescent cells tended to use distal poly(A) (pA) sites, leading to a global lengthening of 3' UTRs and reduced gene expression. Genes that harbor longer 3' UTRs in senescent cells were enriched in senescence-related pathways. Rras2, a member of the Ras superfamily that participates in multiple signal transduction pathways, preferred longer 3' UTR usage and exhibited decreased expression in senescent cells. Depletion of Rras2 promoted senescence, while rescue of Rras2 reversed senescence-associated phenotypes. Mechanistically, splicing factor TRA2B bound to a core "AGAA" motif located in the alternative 3' UTR of Rras2, thereby reducing the RRAS2 protein level and causing senescence. Both proximal and distal poly(A) signals showed strong sequence conservation, highlighting the vital role of APA regulation during evolution. Our results revealed APA as a novel mechanism in regulating cellular senescence.
Collapse
Affiliation(s)
- Meng Chen
- State Key Laboratory of Genetic Engineering and Ministry of Education (MOE) Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438 China
| | - Guoliang Lyu
- MOE Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, 100871 China
| | - Miao Han
- State Key Laboratory of Genetic Engineering and Ministry of Education (MOE) Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438 China
| | - Hongbo Nie
- State Key Laboratory of Genetic Engineering and Ministry of Education (MOE) Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438 China
| | - Ting Shen
- State Key Laboratory of Genetic Engineering and Ministry of Education (MOE) Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438 China
| | - Wei Chen
- State Key Laboratory of Genetic Engineering and Ministry of Education (MOE) Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438 China
| | - Yichi Niu
- State Key Laboratory of Genetic Engineering and Ministry of Education (MOE) Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438 China
| | - Yifan Song
- State Key Laboratory of Genetic Engineering and Ministry of Education (MOE) Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438 China
| | - Xueping Li
- State Key Laboratory of Genetic Engineering and Ministry of Education (MOE) Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438 China
| | - Huan Li
- State Key Laboratory of Genetic Engineering and Ministry of Education (MOE) Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438 China
| | - Xinyu Chen
- State Key Laboratory of Genetic Engineering and Ministry of Education (MOE) Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438 China
| | - Ziyue Wang
- State Key Laboratory of Genetic Engineering and Ministry of Education (MOE) Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438 China
| | - Zheng Xia
- Division of Biostatistics, Dan L. Duncan Cancer Center and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Wei Li
- Division of Biostatistics, Dan L. Duncan Cancer Center and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | - Xiao-Li Tian
- Human Aging Research Institute and School of Life Sciences, Nanchang University, Nanchang, 330031 China
| | - Chen Ding
- State Key Laboratory of Genetic Engineering, Collaborative Innovation Center of Genetics and Development, School of Life Sciences, Fudan University, Shanghai, 200438 China
| | - Jun Gu
- MOE Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, 100871 China
| | - Yufang Zheng
- State Key Laboratory of Genetic Engineering and Ministry of Education (MOE) Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438 China
| | - Xinhua Liu
- School of Pharmacy, Fudan University, Shanghai, 201203 China
| | - Jinfeng Hu
- School of Pharmacy, Fudan University, Shanghai, 201203 China
| | - Gang Wei
- State Key Laboratory of Genetic Engineering and Ministry of Education (MOE) Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438 China
| | - Wei Tao
- MOE Key Laboratory of Cell Proliferation and Differentiation, School of Life Sciences, Peking University, Beijing, 100871 China
| | - Ting Ni
- State Key Laboratory of Genetic Engineering and Ministry of Education (MOE) Key Laboratory of Contemporary Anthropology, Collaborative Innovation Center of Genetics and Development, School of Life Sciences and Huashan Hospital, Fudan University, Shanghai, 200438 China
| |
Collapse
|
7
|
Cavinato M, Koziel R, Romani N, Weinmüllner R, Jenewein B, Hermann M, Dubrac S, Ratzinger G, Grillari J, Schmuth M, Jansen-Dürr P. UVB-Induced Senescence of Human Dermal Fibroblasts Involves Impairment of Proteasome and Enhanced Autophagic Activity. J Gerontol A Biol Sci Med Sci 2017; 72:632-639. [PMID: 27516623 DOI: 10.1093/gerona/glw150] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/14/2016] [Indexed: 12/15/2022] Open
Abstract
In the current study, we have extended previous findings aiming at a better understanding of molecular mechanisms underlying UVB-induced senescence of diploid human dermal fibroblasts (HDFs), an experimental model to study the process of photoaging in the skin. We provide evidence that the inhibition of proteasomal degradation of damaged proteins and the activation of autophagosome formation are early events in UVB-induced senescence of HDFs, dependent on UVB-induced accumulation of reactive oxygen species. Our data suggest that autophagy is required for the establishment of the senescent phenotype in UVB-treated HDFs and that inhibition of autophagy is sufficient to change the cell fate from senescence to cell death by apoptosis. Studies in reconstructed skin equivalents revealed that UVB irradiation triggers hallmarks of autophagy induction in the dermal layer. These findings have potential implications for fundamental as well as translational research into skin aging, in particular photoaging.
Collapse
Affiliation(s)
- Maria Cavinato
- Institute for Biomedical Aging Research, Universität Innsbruck, Austria
| | - Rafal Koziel
- Institute for Biomedical Aging Research, Universität Innsbruck, Austria
| | - Nikolaus Romani
- Department of Dermatology and Venerology, Medical University of Innsbruck, Austria
| | - Regina Weinmüllner
- Christian Doppler Laboratory on Biotechnology of Skin Aging, Department of Biotechnology, BOKU-University of Natural Resources and Life Sciences Vienna, Austria
| | - Brigitte Jenewein
- Institute for Biomedical Aging Research, Universität Innsbruck, Austria
| | - Martin Hermann
- Department of Anaesthesiology and Critical Care Medicine, Medical University of Innsbruck, Austria
| | - Sandrine Dubrac
- Department of Dermatology and Venerology, Medical University of Innsbruck, Austria
| | - Gudrun Ratzinger
- Department of Dermatology and Venerology, Medical University of Innsbruck, Austria
| | - Johannes Grillari
- Christian Doppler Laboratory on Biotechnology of Skin Aging, Department of Biotechnology, BOKU-University of Natural Resources and Life Sciences Vienna, Austria
| | - Matthias Schmuth
- Department of Dermatology and Venerology, Medical University of Innsbruck, Austria
| | | |
Collapse
|
8
|
Saeed H, Qiu W, Li C, Flyvbjerg A, Abdallah BM, Kassem M. Telomerase activity promotes osteoblast differentiation by modulating IGF-signaling pathway. Biogerontology 2015; 16:733-45. [PMID: 26260615 PMCID: PMC4602053 DOI: 10.1007/s10522-015-9596-6] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2015] [Accepted: 07/27/2015] [Indexed: 12/15/2022]
Abstract
The contribution of deficient telomerase activity to age-related decline in osteoblast functions and bone formation is poorly studied. We have previously demonstrated that telomerase over-expression led to enhanced osteoblast differentiation of human bone marrow skeletal (stromal) stem cells (hMSC) in vitro and in vivo. Here, we investigated the signaling pathways underlying the regulatory functions of telomerase in osteoblastic cells. Comparative microarray analysis and Western blot analysis of telomerase-over expressing hMSC (hMSC-TERT) versus primary hMSC revealed significant up-regulation of several components of insulin-like growth factor (IGF) signaling. Specifically, a significant increase in IGF-induced AKT phosphorylation and alkaline phosphatase (ALP) activity were observed in hMSC-TERT. Enhanced ALP activity was reduced in presence of IGF1 receptor inhibitor: picropodophyllin. In addition, telomerase deficiency caused significant reduction in IGF signaling proteins in osteoblastic cells cultured from telomerase deficient mice (Terc(-/-)). The low bone mass exhibited by Terc(-/-) mice was associated with significant reduction in serum levels of IGF1 and IGFBP3 as well as reduced skeletal mRNA expression of Igf1, Igf2, Igf2r, Igfbp5 and Igfbp6. IGF1-induced osteoblast differentiation was also impaired in Terc(-/-) MSC. In conclusion, our data demonstrate that impaired IGF/AKT signaling contributes to the observed decreased bone mass and bone formation exhibited by telomerase deficient osteoblastic cells.
Collapse
Affiliation(s)
- Hamid Saeed
- Molecular Endocrinology Laboratory (KMEB), Department of Endocrinology and Metabolism, Medical Biotechnology Center, Odense University Hospital & University of Southern Denmark, SDU, 5000, Odense C, Denmark. .,University College of Pharmacy, Punjab University, Allama Iqbal Campus, Lahore, 54000, Pakistan.
| | - Weimin Qiu
- Molecular Endocrinology Laboratory (KMEB), Department of Endocrinology and Metabolism, Medical Biotechnology Center, Odense University Hospital & University of Southern Denmark, SDU, 5000, Odense C, Denmark.
| | - Chen Li
- Molecular Endocrinology Laboratory (KMEB), Department of Endocrinology and Metabolism, Medical Biotechnology Center, Odense University Hospital & University of Southern Denmark, SDU, 5000, Odense C, Denmark.
| | - Allan Flyvbjerg
- Department of Endcrinology, University Hosptial of Aarhus, 8000, Aarhus C, Denmark.
| | - Basem M Abdallah
- Molecular Endocrinology Laboratory (KMEB), Department of Endocrinology and Metabolism, Medical Biotechnology Center, Odense University Hospital & University of Southern Denmark, SDU, 5000, Odense C, Denmark. .,Faculty of Scince, Helwan University, Cairo, Egypt.
| | - Moustapha Kassem
- Molecular Endocrinology Laboratory (KMEB), Department of Endocrinology and Metabolism, Medical Biotechnology Center, Odense University Hospital & University of Southern Denmark, SDU, 5000, Odense C, Denmark. .,Stem Cell Unit, King Saud University, Riyadh, Saudi Arabia.
| |
Collapse
|
9
|
Abstract
Endothelial cells line blood vessels and modulate vascular tone, thrombosis, inflammatory responses and new vessel formation. They are implicated in many disease processes including atherosclerosis and cancer. IGFs play a significant role in the physiology of endothelial cells by promoting migration, tube formation and production of the vasodilator nitric oxide. These actions are mediated by the IGF1 and IGF2/mannose 6-phosphate receptors and are modulated by a family of high-affinity IGF binding proteins. IGFs also increase the number and function of endothelial progenitor cells, which may contribute to protection from atherosclerosis. IGFs promote angiogenesis, and dysregulation of the IGF system may contribute to this process in cancer and eye diseases including retinopathy of prematurity and diabetic retinopathy. In some situations, IGF deficiency appears to contribute to endothelial dysfunction, whereas IGF may be deleterious in others. These differences may be due to tissue-specific endothelial cell phenotypes or IGFs having distinct roles in different phases of vascular disease. Further studies are therefore required to delineate the therapeutic potential of IGF system modulation in pathogenic processes.
Collapse
Affiliation(s)
- Leon A Bach
- Department of Medicine (Alfred)Monash University, Prahran 3181, AustraliaDepartment of Endocrinology and DiabetesAlfred Hospital, Commercial Road, Melbourne 3004, Australia Department of Medicine (Alfred)Monash University, Prahran 3181, AustraliaDepartment of Endocrinology and DiabetesAlfred Hospital, Commercial Road, Melbourne 3004, Australia
| |
Collapse
|
10
|
Hawsawi Y, El-Gendy R, Twelves C, Speirs V, Beattie J. Insulin-like growth factor - oestradiol crosstalk and mammary gland tumourigenesis. Biochim Biophys Acta Rev Cancer 2013; 1836:345-53. [PMID: 24189571 DOI: 10.1016/j.bbcan.2013.10.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 10/15/2013] [Accepted: 10/24/2013] [Indexed: 12/22/2022]
Abstract
Development and differentiation of the mammary gland are dependent on the appropriate temporal expression of both systemically acting hormones and locally produced growth factors. A large body of evidence suggests that molecular crosstalk between these hormonal and growth factor axes is crucial for appropriate cell and tissue function. Two of the most important trophic factors involved in this process are the oestrogen (E) and insulin-like growth factor (IGF) molecular axes. The reciprocal crosstalk that exists between these pathways occurs at transcriptional/post-transcriptional and translational/post-translational levels regulate the expression and activity of genes involved in this process. In a clinical context an important consequence of such crosstalk in the mammary gland is the role which it may play in the aetiology, maintenance and development of breast tumours. Although oestradiol (E2) acting through oestrogen receptors α and β (ERα/β) is important for normal mammary gland function it can also provide a mitogenic drive to ER+ breast tumours. Therefore over several years anti-oestrogen therapeutic regimens in the form of selective oestrogen receptor modulators (SERMs - e.g. tamoxifen), aromatase inhibitors (AI e.g. anastrozole) or selective oestrogen receptor down regulators (SERDs - e.g. fulvestrant) have been used in an adjuvant setting to control tumour growth. Although initial response is usually encouraging, large cohorts of patients eventually develop resistance to these treatments leading to tumour recurrence and poor prognosis. There are potentially many routes by which breast cancer (BC) cells could escape anti-oestrogen based therapeutic strategies and one of the most studied is the possible growth factor mediated activation of ER(s). Because of this, growth factor modulation of ER activity has been an intensively studied route of molecular crosstalk in the mammary gland. The insulin-like growth factors (IGF-1 and -2) are amongst the most potent mitogens for mammary epithelial cells and there is accumulating evidence that they interact with the E2 axis to regulate mitogenesis, apoptosis, adhesion, migration and differentiation of mammary epithelial cells. Such interactions are bi-directional and E2 has been shown to regulate the expression and activity of IGF axis genes with the general effect of sensitising breast epithelial cells to the actions of IGFs and insulin. In this short review we discuss the evidence for the involvement of crosstalk between the insulin-like growth factor (IGF) and oestrogen axes in the mammary gland and comment on the relevance of such studies in the aetiology and treatment of BC.
Collapse
|
11
|
Sampson N, Zenzmaier C, Heitz M, Hermann M, Plas E, Schäfer G, Klocker H, Berger P. Stromal insulin-like growth factor binding protein 3 (IGFBP3) is elevated in the diseased human prostate and promotes ex vivo fibroblast-to-myofibroblast differentiation. Endocrinology 2013; 154:2586-99. [PMID: 23720424 DOI: 10.1210/en.2012-2259] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Dysregulation of the IGF axis is implicated in the development of benign prostatic hyperplasia (BPH) and prostate cancer (PCa), 2 of the most common diseases affecting elderly males. PCa is the second leading cause of male-related cancer death in Western societies. Although distinct pathologies, BPH and PCa are both characterized by extensive stromal remodeling, in particular fibroblast-to-myofibroblast differentiation, thought to be induced by elevated local production of TGFβ1. We previously showed that TGFβ1-mediated fibroblast-to-myofibroblast differentiation of primary human prostatic stromal cells resulted in the dsyregulation of several components of the IGF axis, including the induction of IGF binding protein 3 (IGFBP3). Using isoform-specific lentiviral-mediated knockdown, we demonstrate herein that IGFBP3 is essential for TGFβ1-mediated differentiation. Although recombinant human IGFBP3 alone was not sufficient to induce differentiation, IGFBP3 synergistically potentiated TGFβ1-mediated stromal remodeling predominantly via an IGF-independent mechanism. Consistent with these in vitro findings, IGFBP3 immunohistochemistry revealed elevated levels of IGFBP3 in the hyperplastic fibromuscular stroma of BPH specimens and in the tumor-adjacent stroma of high-grade PCa. Collectively these data indicate that the dysregulation of the stromal IGF axis, in particular elevated IGFBP3, plays a crucial role in fibroblast-to-myofibroblast differentiation in the diseased prostatic stroma and indicate the therapeutic potential of inhibiting stromal remodeling and the resulting dysregulation of the stromal IGF axis as a novel strategy for the treatment of advanced PCa and BPH.
Collapse
|
12
|
Nelson G, Wordsworth J, Wang C, Jurk D, Lawless C, Martin‐Ruiz C, von Zglinicki T. A senescent cell bystander effect: senescence-induced senescence. Aging Cell 2012; 11:345-9. [PMID: 22321662 PMCID: PMC3488292 DOI: 10.1111/j.1474-9726.2012.00795.x] [Citation(s) in RCA: 646] [Impact Index Per Article: 53.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Senescent cells produce and secrete various bioactive molecules including interleukins, growth factors, matrix-degrading enzymes and reactive oxygen species (ROS). Thus, it has been proposed that senescent cells can damage their local environment, and a stimulatory effect on tumour cell growth and invasiveness has been documented. However, it was unknown what effect, if any, senescent cells have on their normal, proliferation-competent counterparts. We show here that senescent cells induce a DNA damage response, characteristic for senescence, in neighbouring cells via gap junction-mediated cell–cell contact and processes involving ROS. Continuous exposure to senescent cells induced cell senescence in intact bystander fibroblasts. Hepatocytes bearing senescence markers clustered together in mice livers. Thus, senescent cells can induce a bystander effect, spreading senescence towards their neighbours in vitro and, possibly, in vivo.
Collapse
Affiliation(s)
- Glyn Nelson
- Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, UK
| | - James Wordsworth
- Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, UK
| | - Chunfang Wang
- Department of Life Science, Walton Hall, Open University, Milton Keynes, MK7 6AA, UK
| | - Diana Jurk
- Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, UK
| | - Conor Lawless
- Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, UK
| | - Carmen Martin‐Ruiz
- Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, UK
| | - Thomas von Zglinicki
- Institute for Ageing and Health, Newcastle University, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, UK
| |
Collapse
|
13
|
Micutkova L, Diener T, Li C, Rogowska-Wrzesinska A, Mueck C, Huetter E, Weinberger B, Grubeck-Loebenstein B, Roepstorff P, Zeng R, Jansen-Duerr P. Insulin-like growth factor binding protein-6 delays replicative senescence of human fibroblasts. Mech Ageing Dev 2011; 132:468-79. [PMID: 21820463 PMCID: PMC3192261 DOI: 10.1016/j.mad.2011.07.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2010] [Revised: 07/08/2011] [Accepted: 07/15/2011] [Indexed: 01/10/2023]
Abstract
Cellular senescence can be induced by a variety of mechanisms, and recent data suggest a key role for cytokine networks to maintain the senescent state. Here, we have used a proteomic LC-MS/MS approach to identify new extracellular regulators of senescence in human fibroblasts. We identified 26 extracellular proteins with significantly different abundance in conditioned media from young and senescent fibroblasts. Among these was insulin-like growth factor binding protein-6 (IGFBP-6), which was chosen for further analysis. When IGFBP-6 gene expression was downregulated, cell proliferation was inhibited and apoptotic cell death was increased. Furthermore, downregulation of IGFBP-6 led to premature entry into cellular senescence. Since IGFBP-6 overexpression increased cellular lifespan, the data suggest that IGFBP-6, in contrast to other IGF binding proteins, is a negative regulator of cellular senescence in human fibroblasts.
Collapse
Affiliation(s)
- Lucia Micutkova
- Institute for Biomedical Aging Research, Austrian Academy of Sciences, Rennweg 10, A-6020 Innsbruck, Austria
| | - Thomas Diener
- Institute for Biomedical Aging Research, Austrian Academy of Sciences, Rennweg 10, A-6020 Innsbruck, Austria
| | - Chen Li
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Adelina Rogowska-Wrzesinska
- Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK 5230 Odense M, Denmark
| | - Christoph Mueck
- Institute for Biomedical Aging Research, Austrian Academy of Sciences, Rennweg 10, A-6020 Innsbruck, Austria
| | - Eveline Huetter
- Institute for Biomedical Aging Research, Austrian Academy of Sciences, Rennweg 10, A-6020 Innsbruck, Austria
| | - Birgit Weinberger
- Institute for Biomedical Aging Research, Austrian Academy of Sciences, Rennweg 10, A-6020 Innsbruck, Austria
| | - Beatrix Grubeck-Loebenstein
- Institute for Biomedical Aging Research, Austrian Academy of Sciences, Rennweg 10, A-6020 Innsbruck, Austria
| | - Peter Roepstorff
- Protein Research Group, Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK 5230 Odense M, Denmark
| | - Rong Zeng
- Key Laboratory of Systems Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai 200031, China
| | - Pidder Jansen-Duerr
- Institute for Biomedical Aging Research, Austrian Academy of Sciences, Rennweg 10, A-6020 Innsbruck, Austria
- Corresponding author. Tel.: +43 512 583919 44; fax: +43 512 583919 8.
| |
Collapse
|
14
|
Laschober GT, Ruli D, Hofer E, Muck C, Carmona-Gutierrez D, Ring J, Hutter E, Ruckenstuhl C, Micutkova L, Brunauer R, Jamnig A, Trimmel D, Herndler-Brandstetter D, Brunner S, Zenzmaier C, Sampson N, Breitenbach M, Fröhlich KU, Grubeck-Loebenstein B, Berger P, Wieser M, Grillari-Voglauer R, Thallinger GG, Grillari J, Trajanoski Z, Madeo F, Lepperdinger G, Jansen-Dürr P. Identification of evolutionarily conserved genetic regulators of cellular aging. Aging Cell 2010; 9:1084-97. [PMID: 20883526 PMCID: PMC2997327 DOI: 10.1111/j.1474-9726.2010.00637.x] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
To identify new genetic regulators of cellular aging and senescence, we performed genome-wide comparative RNA profiling with selected human cellular model systems, reflecting replicative senescence, stress-induced premature senescence, and distinct other forms of cellular aging. Gene expression profiles were measured, analyzed, and entered into a newly generated database referred to as the GiSAO database. Bioinformatic analysis revealed a set of new candidate genes, conserved across the majority of the cellular aging models, which were so far not associated with cellular aging, and highlighted several new pathways that potentially play a role in cellular aging. Several candidate genes obtained through this analysis have been confirmed by functional experiments, thereby validating the experimental approach. The effect of genetic deletion on chronological lifespan in yeast was assessed for 93 genes where (i) functional homologues were found in the yeast genome and (ii) the deletion strain was viable. We identified several genes whose deletion led to significant changes of chronological lifespan in yeast, featuring both lifespan shortening and lifespan extension. In conclusion, an unbiased screen across species uncovered several so far unrecognized molecular pathways for cellular aging that are conserved in evolution.
Collapse
Affiliation(s)
- Gerhard T Laschober
- Institute for Biomedical Aging Research, Austrian Academy of SciencesRennweg 10, A-6020 Innsbruck, Austria
| | - Doris Ruli
- Institute for Molecular Biosciences, University of GrazHumboldtstrasse 50, 8010 Graz, Austria
| | - Edith Hofer
- Institute for Genomics and Bioinformatics, Graz University of TechnologyPetersgasse 14, 8010 Graz, Austria
| | - Christoph Muck
- Institute for Biomedical Aging Research, Austrian Academy of SciencesRennweg 10, A-6020 Innsbruck, Austria
| | - Didac Carmona-Gutierrez
- Institute for Molecular Biosciences, University of GrazHumboldtstrasse 50, 8010 Graz, Austria
| | - Julia Ring
- Institute for Molecular Biosciences, University of GrazHumboldtstrasse 50, 8010 Graz, Austria
| | - Eveline Hutter
- Institute for Biomedical Aging Research, Austrian Academy of SciencesRennweg 10, A-6020 Innsbruck, Austria
| | - Christoph Ruckenstuhl
- Institute for Molecular Biosciences, University of GrazHumboldtstrasse 50, 8010 Graz, Austria
| | - Lucia Micutkova
- Institute for Biomedical Aging Research, Austrian Academy of SciencesRennweg 10, A-6020 Innsbruck, Austria
| | - Regina Brunauer
- Institute for Biomedical Aging Research, Austrian Academy of SciencesRennweg 10, A-6020 Innsbruck, Austria
| | - Angelika Jamnig
- Institute for Biomedical Aging Research, Austrian Academy of SciencesRennweg 10, A-6020 Innsbruck, Austria
| | - Daniela Trimmel
- Institute for Biomedical Aging Research, Austrian Academy of SciencesRennweg 10, A-6020 Innsbruck, Austria
| | | | - Stefan Brunner
- Institute for Biomedical Aging Research, Austrian Academy of SciencesRennweg 10, A-6020 Innsbruck, Austria
| | - Christoph Zenzmaier
- Institute for Biomedical Aging Research, Austrian Academy of SciencesRennweg 10, A-6020 Innsbruck, Austria
| | - Natalie Sampson
- Institute for Biomedical Aging Research, Austrian Academy of SciencesRennweg 10, A-6020 Innsbruck, Austria
| | | | - Kai-Uwe Fröhlich
- Institute for Molecular Biosciences, University of GrazHumboldtstrasse 50, 8010 Graz, Austria
| | | | - Peter Berger
- Institute for Biomedical Aging Research, Austrian Academy of SciencesRennweg 10, A-6020 Innsbruck, Austria
| | - Matthias Wieser
- Aging and Immortalization Research, Department of Biotechnology, University of Natural Resources and Applied Life SciencesVienna, Austria
| | - Regina Grillari-Voglauer
- Aging and Immortalization Research, Department of Biotechnology, University of Natural Resources and Applied Life SciencesVienna, Austria
| | - Gerhard G Thallinger
- Institute for Genomics and Bioinformatics, Graz University of TechnologyPetersgasse 14, 8010 Graz, Austria
| | - Johannes Grillari
- Aging and Immortalization Research, Department of Biotechnology, University of Natural Resources and Applied Life SciencesVienna, Austria
| | - Zlatko Trajanoski
- Institute for Genomics and Bioinformatics, Graz University of TechnologyPetersgasse 14, 8010 Graz, Austria
- Biocenter, Section for Bioinformatics, Innsbruck Medical UniversityInnsbruck, Austria
| | - Frank Madeo
- Institute for Molecular Biosciences, University of GrazHumboldtstrasse 50, 8010 Graz, Austria
| | - Günter Lepperdinger
- Institute for Biomedical Aging Research, Austrian Academy of SciencesRennweg 10, A-6020 Innsbruck, Austria
| | - Pidder Jansen-Dürr
- Institute for Biomedical Aging Research, Austrian Academy of SciencesRennweg 10, A-6020 Innsbruck, Austria
| |
Collapse
|
15
|
Grillari J, Grillari-Voglauer R. Novel modulators of senescence, aging, and longevity: Small non-coding RNAs enter the stage. Exp Gerontol 2010; 45:302-11. [PMID: 20080172 DOI: 10.1016/j.exger.2010.01.007] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2009] [Revised: 12/08/2009] [Accepted: 01/08/2010] [Indexed: 02/06/2023]
Abstract
During the last decade evidence has accumulated that the aging process is driven by limited allocation of energy to somatic maintenance resulting in accumulation of stochastic damage. This damage, affecting molecules, cells, and tissues, is counteracted by genetically programmed repair, the efficiency of which thus importantly determines the life and 'health span' of organisms. Therefore, understanding the regulation of gene expression during cellular and organismal aging as well as upon exposure to various damaging events is important to understand the biology of aging and to positively influence the health span. The recent identification of small non-coding RNAs (ncRNAs), has added an additional layer of complexity to the regulation of gene expression with the classes of endogenous small inhibitory RNAs (siRNAs), PIWI-interacting RNAs (piRNAs), QDE1-interacting RNAs (qiRNAs) and microRNAs (miRNAs). Some of these ncRNAs have not yet been identified in mammalian cells and are dependent on RNA-dependent RNA polymerases. The first mammalian enzyme with such activity has only now emerged and surprisingly consists of the catalytic subunit of telomerase (hTERT) together with RMPR, an alternative RNA component. The so far most studied small non-coding RNAs, miRNAs, however, are now increasingly found to operate in the complex network of cellular aging. Recent findings show that (i) miRNAs are regulated during cellular senescence in vitro, (ii) they contribute to tissue regeneration by regulation of stem cell function, and (iii) at least one miRNA modulates the life span of the model organism C. elegans. Additionally, (iv) they act as inhibitors of proteins mediating the insulin/IGF1 and target of rapamycin (TOR) signalling, both of which are conserved modulators of organism life span. Here we will give an overview on the current status of these topics. Since little is so far known on the functions of small ncRNAs in the context of aging and longevity, the entry of the RNA world into the field of biogerontology certainly holds additional surprises and promises. Even more so, as miRNAs are implicated in many age-associated pathologies, and as RNAi and miRNA based therapeutics are on their way to clinics.
Collapse
Affiliation(s)
- Johannes Grillari
- Department of Biotechnology, University of Natural Resources and Applied Life Sciences Vienna, Austria.
| | | |
Collapse
|
16
|
Abstract
The free radical theory of aging proposes that ROS (reactive oxygen species) are major driving forces of aging, and are also critically involved in cellular senescence. Besides the mitochondrial respiratory chain, alternative sources of ROS have been described that might contribute to cellular senescence. Noxs (NADPH oxidases) are well-known sources of superoxide, which contribute to the antimicrobial capabilities of macrophages, a process involving the prototypical member of the family referred to as Nox2. However, in recent years non-phagocytic homologues of Nox2 have been identified that are involved in processes other than the host defence. Superoxide anions produced by these enzymes are believed to play a major role in signalling by MAPKs (mitogen-activated protein kinases) and stress-activated kinases, but could also contribute to cellular senescence, which is known to involve oxygen radicals. In HUVECs (human umbilical vein endothelial cells), Nox4 is predominantly expressed, but its role in replicative senescence of HUVECs remains to be elucidated. Using shRNA (small-hairpin RNA)-mediated knockdown of Nox4, implicating lentiviral vectors, we addressed the question of whether lifelong depletion of Nox4 in HUVECs would influence the senescent phenotype. We found a significant extension of the replicative lifespan of HUVECs upon knockdown of Nox4. Surprisingly, mean telomere length was significantly reduced in Nox4-depleted cells. Nox4 depletion had no discernable influence on the activity of MAPKs and stress-activated kinases, but reduced the degree of oxidative DNA damage. These results suggest that Nox4 activity increases oxidative damage in HUVECs, leading to loss of replicative potential, which is at least partly independent of telomere attrition.
Collapse
|
17
|
Re RN, Cook JL. Senescence, apoptosis, and stem cell biology: the rationale for an expanded view of intracrine action. Am J Physiol Heart Circ Physiol 2009; 297:H893-901. [PMID: 19592610 PMCID: PMC2755987 DOI: 10.1152/ajpheart.00414.2009] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2009] [Accepted: 07/02/2009] [Indexed: 12/28/2022]
Abstract
Some extracellular-signaling peptides also at times function within the intracellular space. We have termed these peptides intracrines and have argued that intracrine function is associated with a wide variety of peptides/proteins including hormones, growth factors, cytokines, enzymes, and DNA-binding proteins among others. Here we consider the possibility that intracrines participate in the related phenomena of senescence, apoptosis, and stem cell regulation of tissue biology. Based on this analysis, we also suggest that the concept of intracrine action be expanded to include possible regulatory peptide transfer via exosomes/microvesicles and possibly by nanotubes. Moreover, the process of microvesicular and nanotube transfer of peptides and other biologically relevant molecules, which we inclusively term laterality, is explored. These notions have potentially important therapeutic implications, including implications for the therapy of cardiovascular disease.
Collapse
Affiliation(s)
- Richard N Re
- Ochsner Clinic Foundation, New Orleans, LA 70121, USA.
| | | |
Collapse
|
18
|
Abstract
Oncogene-induced cellular senescence constitutes a strong anti-proliferative response, which can be set in motion following either oncogene activation or loss of tumour suppressor signalling. It serves to limit the expansion of early neoplastic cells and as such is a potent cancer-protective response to oncogenic events. Recently emerging evidence points to a crucial role in oncogene-induced cellular senescence for the 'senescence-messaging secretome' or SMS, setting the stage for cross-talk between senescent cells and their environment. How are such signals integrated into a coordinated response and what are the implications of this unexpected finding?
Collapse
Affiliation(s)
- Thomas Kuilman
- Division of Molecular Genetics, The Netherlands Cancer Institute, Plesmanlaan 121, 1066 CX Amsterdam, the Netherlands
| | | |
Collapse
|