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Podgrajsek R, Ban Frangez H, Stimpfel M. Molecular Mechanism of Resveratrol and Its Therapeutic Potential on Female Infertility. Int J Mol Sci 2024; 25:3613. [PMID: 38612425 PMCID: PMC11011890 DOI: 10.3390/ijms25073613] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2024] [Revised: 03/19/2024] [Accepted: 03/19/2024] [Indexed: 04/14/2024] Open
Abstract
Resveratrol is a polyphenol present in various plant sources. Studies have reported numerous potential health benefits of resveratrol, exhibiting anti-aging, anti-inflammatory, anti-microbial, and anti-carcinogenic activity. Due to the reported effects, resveratrol is also being tested in reproductive disorders, including female infertility. Numerous cellular, animal, and even human studies were performed with a focus on the effect of resveratrol on female infertility. In this review, we reviewed some of its molecular mechanisms of action and summarized animal and human studies regarding resveratrol and female infertility, with a focus on age-related infertility, polycystic ovary syndrome, and endometriosis.
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Affiliation(s)
- Rebeka Podgrajsek
- Department of Human Reproduction, Division of Obstetrics and Gynecology, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (R.P.); (H.B.F.)
| | - Helena Ban Frangez
- Department of Human Reproduction, Division of Obstetrics and Gynecology, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (R.P.); (H.B.F.)
- Medical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
| | - Martin Stimpfel
- Department of Human Reproduction, Division of Obstetrics and Gynecology, University Medical Centre Ljubljana, 1000 Ljubljana, Slovenia; (R.P.); (H.B.F.)
- Medical Faculty, University of Ljubljana, 1000 Ljubljana, Slovenia
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2
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Mc Auley MT. Modeling cholesterol metabolism and atherosclerosis. WIREs Mech Dis 2021; 14:e1546. [PMID: 34931487 DOI: 10.1002/wsbm.1546] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 10/11/2021] [Accepted: 10/14/2021] [Indexed: 12/19/2022]
Abstract
Atherosclerotic cardiovascular disease (ASCVD) is the leading cause of morbidity and mortality among Western populations. Many risk factors have been identified for ASCVD; however, elevated low-density lipoprotein cholesterol (LDL-C) remains the gold standard. Cholesterol metabolism at the cellular and whole-body level is maintained by an array of interacting components. These regulatory mechanisms have complex behavior. Likewise, the mechanisms which underpin atherogenesis are nontrivial and multifaceted. To help overcome the challenge of investigating these processes mathematical modeling, which is a core constituent of the systems biology paradigm has played a pivotal role in deciphering their dynamics. In so doing models have revealed new insights about the key drivers of ASCVD. The aim of this review is fourfold; to provide an overview of cholesterol metabolism and atherosclerosis, to briefly introduce mathematical approaches used in this field, to critically discuss models of cholesterol metabolism and atherosclerosis, and to highlight areas where mathematical modeling could help to investigate in the future. This article is categorized under: Cardiovascular Diseases > Computational Models.
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Electrochemically detecting DNA methylation in the EN1 gene promoter: implications for understanding ageing and disease. Biosci Rep 2021; 40:226876. [PMID: 33135722 PMCID: PMC7670582 DOI: 10.1042/bsr20202571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Revised: 09/29/2020] [Accepted: 10/28/2020] [Indexed: 12/12/2022] Open
Abstract
There is a growing need for biomarkers which predict age-onset pathology. Although this is challenging, the methylome offers significant potential. Cancer is associated with the hypermethylation of many gene promoters, among which are developmental genes. Evolutionary theory suggests developmental genes arbitrate early-late life trade-offs, causing epimutations that increase disease vulnerability. Such genes could predict age-related disease. The aim of this work was to optimise an electrochemical procedure for the future investigation of a broad range of ageing-related pathologies. An electrochemical approach, which adopted three analytical techniques, was used to investigate DNA methylation in the engrailed-1 (EN1) gene promoter. Using synthetic single-stranded DNA, one technique was able to detect DNA at concentrations as low as 10 nM, with methylation status distinguishable at concentrations >25 nM. A negative correlation could be observed between % methylation of a heterogeneous solution and the key electrochemical parameter, charge transfer resistance (Rct; r = -0.982, P<0.01). The technique was applied to the breast cancer cell line Michigan Cancer Foundation-7 (MCF-7), where a similar correlation was observed (r = -0.965, P<0.01). These results suggest electrochemistry can effectively measure DNA methylation at low concentrations of DNA. This has implications for the future detection of age-related disease.
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Morgan AE, Mc Auley MT. Cholesterol Homeostasis: An In Silico Investigation into How Aging Disrupts Its Key Hepatic Regulatory Mechanisms. BIOLOGY 2020; 9:E314. [PMID: 33007859 PMCID: PMC7599957 DOI: 10.3390/biology9100314] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2020] [Revised: 09/21/2020] [Accepted: 09/24/2020] [Indexed: 12/17/2022]
Abstract
The dysregulation of intracellular cholesterol homeostasis is associated with several age-related diseases, most notably cardiovascular disease (CVD). Research in this area has benefitted from using computational modelling to study the inherent complexity associated with the regulation of this system. In addition to facilitating hypothesis exploration, the utility of modelling lies in its ability to represent an array of rate limiting enzymatic reactions, together with multiple feedback loops, which collectively define the dynamics of cholesterol homeostasis. However, to date no model has specifically investigated the effects aging has on this system. This work addresses this shortcoming by explicitly focusing on the impact of aging on hepatic intracellular cholesterol homeostasis. The model was used to investigate the experimental findings that reactive oxygen species induce the total activation of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (HMGCR). Moreover, the model explored the impact of an age-related decrease in hepatic acetyl-CoA acetyltransferase 2 (ACAT2). The model suggested that an increase in the activity of HMGCR does not have as significant an impact on cholesterol homeostasis as a decrease in hepatic ACAT2 activity. According to the model, a decrease in the activity of hepatic ACAT2 raises free cholesterol (FC) and decreases low-density lipoprotein cholesterol (LDL-C) levels. Increased acetyl CoA synthesis resulted in a reduction in the number of hepatic low-density lipoprotein receptors, and increased LDL-C, FC, and cholesterol esters. The rise in LDL-C was restricted by elevated hepatic FC accumulation. Taken together these findings have important implications for healthspan. This is because emerging clinical data suggest hepatic FC accumulation is relevant to the pathogenesis of non-alcoholic fatty liver disease (NAFLD), which is associated with an increased risk of CVD. These pathophysiological changes could, in part, help to explain the phenomenon of increased mortality associated with low levels of LDL-C which have been observed in certain studies involving the oldest old (≥85 years).
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Affiliation(s)
| | - Mark Tomás Mc Auley
- Faculty of Science and Engineering, University of Chester, Thornton Science Park, Chester CH2 4NU, UK;
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5
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Muñoz MF, Argüelles S, Marotta F, Barbagallo M, Cano M, Ayala A. Effect of Age and Lipoperoxidation in Rat and Human Adipose Tissue-Derived Stem Cells. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2020; 2020:6473279. [PMID: 33425211 PMCID: PMC7775166 DOI: 10.1155/2020/6473279] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Revised: 11/08/2020] [Accepted: 11/19/2020] [Indexed: 02/07/2023]
Abstract
A wide range of clinical applications in regenerative medicine were opened decades ago with the discovery of adult stem cells. Highly promising adult stem cells are mesenchymal stem/stromal cells derived from adipose tissue (ADSCs), primarily because of their abundance and accessibility. These cells have multipotent properties and have been used extensively to carry out autologous transplants. However, the biology of these cells is not entirely understood. Among other factors, the regeneration capacity of these cells will depend on both their capacity of proliferation/differentiation and the robustness of the biochemical pathways that allow them to survive under adverse conditions like those found in damaged tissues. The transcription factors, such as Nanog and Sox2, have been described as playing an important role in stem cell proliferation and differentiation. Also, the so-called longevity pathways, in which AMPK and SIRT1 proteins play a crucial role, are essential for cell homeostasis under stressful situations. These pathways act by inhibiting the translation through downregulation of elongation factor-2 (eEF2). In order to deepen knowledge of mesenchymal stem cell biology and which factors are determinant in the final therapeutic output, we evaluate in the present study the levels of all of these proteins in the ADSCs from humans and rats and how these levels are affected by aging and the oxidative environment. Due to the effect of aging and oxidative stress, our results suggest that before performing a cell therapy with ADSCs, several aspects reported in this study such as oxidative stress status and proliferation and differentiation capacity should be assessed on these cells. This would allow us to know the robustness of the transplanted cells and to predict the therapeutic result, especially in elder patients, where probably ADSCs do not carry out their biological functions in an optimal way.
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Affiliation(s)
- Mario F. Muñoz
- 1Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Spain
| | - Sandro Argüelles
- 2Departamento de Fisiología, Facultad de Farmacia, Universidad de Sevilla, Spain
| | - Francesco Marotta
- 3ReGenera R&D International for Aging Intervention & Vitality Therapeutics, San Babila Clinic, Milan, Italy
| | - Mario Barbagallo
- 4Department of Geriatrics and Internal Medicine, University of Palermo, Italy
| | - Mercedes Cano
- 2Departamento de Fisiología, Facultad de Farmacia, Universidad de Sevilla, Spain
| | - Antonio Ayala
- 1Departamento de Bioquímica y Biología Molecular, Facultad de Farmacia, Universidad de Sevilla, Spain
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6
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Brooks DL, Garza AE, Katayama IA, Romero JR, Adler GK, Pojoga LH, Williams GH. Aldosterone Modulates the Mechanistic Target of Rapamycin Signaling in Male Mice. Endocrinology 2019; 160:716-728. [PMID: 30726893 PMCID: PMC6397424 DOI: 10.1210/en.2018-00989] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Accepted: 01/31/2019] [Indexed: 12/12/2022]
Abstract
Both mechanistic target of rapamycin (mTOR) pathway and aldosterone are implicated in the development of cardiovascular and renal disease. However, the interaction between aldosterone and the mTOR pathway is unknown. We hypothesized the following: that (i) increased aldosterone will modulate the activity of the mTORC1 and mTORC2 molecular pathways in the heart and kidney; (ii) a physiologic increase in aldosterone will affect these pathways differently than a pathophysiologic one; and (iii) the changes in the mTOR level/activity will differ between the heart and kidney. In both kidney and heart tissues, phosphorylation of mTOR is significantly decreased when aldosterone levels are physiologically increased (by dietary sodium restriction), followed by a decrease in phosphorylated p70S6K1 in cardiac, but not renal, tissue. Sirtuin 1, an epigenetic modulator, is decreased in the heart but increased in the kidney. Conversely, pathophysiologic aldosterone levels (an infusion for 3 weeks) had divergent effects on phosphorylated mTOR and the downstream substrates of mTORC1 and mTORC2 in cardiac and renal tissues. Increased aldosterone levels significantly alter mTOR activity in the heart and kidney. In the kidney, substantial differences were noted if the increase was produced physiologically vs pathophysiologically, suggesting that mTOR activity, in part, may mediate aldosterone-induced renal damage. Thus, modulating mTOR activity may reduce aldosterone-dependent renal damage similar to mineralocorticoid receptor blockade but potentially with less adverse side effects.
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Affiliation(s)
- Danielle L Brooks
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Boston, Massachusetts
- Correspondence: Danielle L. Brooks, PhD, Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, 221 Longwood Avenue, Boston, Massachusetts 02115. E-mail:
| | - Amanda E Garza
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Boston, Massachusetts
| | - Isis A Katayama
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Boston, Massachusetts
| | - Jose R Romero
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Boston, Massachusetts
| | - Gail K Adler
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Boston, Massachusetts
| | - Luminita H Pojoga
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Boston, Massachusetts
| | - Gordon H Williams
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Boston, Massachusetts
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7
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Jin M, Li Y, O'Laughlin R, Bittihn P, Pillus L, Tsimring LS, Hasty J, Hao N. Divergent Aging of Isogenic Yeast Cells Revealed through Single-Cell Phenotypic Dynamics. Cell Syst 2019; 8:242-253.e3. [PMID: 30852250 DOI: 10.1016/j.cels.2019.02.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 11/28/2018] [Accepted: 02/07/2019] [Indexed: 12/27/2022]
Abstract
Although genetic mutations that alter organisms' average lifespans have been identified in aging research, our understanding of the dynamic changes during aging remains limited. Here, we integrate single-cell imaging, microfluidics, and computational modeling to investigate phenotypic divergence and cellular heterogeneity during replicative aging of single S. cerevisiae cells. Specifically, we find that isogenic cells diverge early in life toward one of two aging paths, which are characterized by distinct age-associated phenotypes. We captured the dynamics of single cells along the paths with a stochastic discrete-state model, which accurately predicts both the measured heterogeneity and the lifespan of cells on each path within a cell population. Our analysis suggests that genetic and environmental factors influence both a cell's choice of paths and the kinetics of paths themselves. Given that these factors are highly conserved throughout eukaryotes, divergent aging might represent a general scheme in cellular aging of other organisms.
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Affiliation(s)
- Meng Jin
- BioCircuits Institute, University of California, San Diego, La Jolla, San Diego, CA 92093, USA
| | - Yang Li
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, San Diego, CA 92093, USA
| | - Richard O'Laughlin
- Department of Bioengineering, University of California, San Diego, La Jolla, San Diego, CA 92093, USA
| | - Philip Bittihn
- BioCircuits Institute, University of California, San Diego, La Jolla, San Diego, CA 92093, USA
| | - Lorraine Pillus
- Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, San Diego, CA 92093, USA; UCSD Moores Cancer Center, University of California, San Diego, La Jolla, San Diego, CA 92093, USA
| | - Lev S Tsimring
- BioCircuits Institute, University of California, San Diego, La Jolla, San Diego, CA 92093, USA.
| | - Jeff Hasty
- BioCircuits Institute, University of California, San Diego, La Jolla, San Diego, CA 92093, USA; Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, San Diego, CA 92093, USA; Department of Bioengineering, University of California, San Diego, La Jolla, San Diego, CA 92093, USA.
| | - Nan Hao
- BioCircuits Institute, University of California, San Diego, La Jolla, San Diego, CA 92093, USA; Section of Molecular Biology, Division of Biological Sciences, University of California, San Diego, La Jolla, San Diego, CA 92093, USA.
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8
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Mc Auley MT, Mooney KM, Salcedo-Sora JE. Computational modelling folate metabolism and DNA methylation: implications for understanding health and ageing. Brief Bioinform 2019; 19:303-317. [PMID: 28007697 DOI: 10.1093/bib/bbw116] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Indexed: 11/12/2022] Open
Abstract
Dietary folates have a key role to play in health, as deficiencies in the intake of these B vitamins have been implicated in a wide variety of clinical conditions. The reason for this is folates function as single carbon donors in the synthesis of methionine and nucleotides. Moreover, folates have a vital role to play in the epigenetics of mammalian cells by supplying methyl groups for DNA methylation reactions. Intriguingly, a growing body of experimental evidence suggests that DNA methylation status could be a central modulator of the ageing process. This has important health implications because the methylation status of the human genome could be used to infer age-related disease risk. Thus, it is imperative we further our understanding of the processes which underpin DNA methylation and how these intersect with folate metabolism and ageing. The biochemical and molecular mechanisms, which underpin these processes, are complex. However, computational modelling offers an ideal framework for handling this complexity. A number of computational models have been assembled over the years, but to date, no model has represented the full scope of the interaction between the folate cycle and the reactions, which governs the DNA methylation cycle. In this review, we will discuss several of the models, which have been developed to represent these systems. In addition, we will present a rationale for developing a combined model of folate metabolism and the DNA methylation cycle.
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Affiliation(s)
- Mark T Mc Auley
- Department of Chemical Engineering, Thornton Science Park, University of Chester, UK
| | - Kathleen M Mooney
- Faculty of Health and Social Care, Edge Hill University, Ormskirk, Lancashire, UK
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9
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Abstract
The last few decades have witnessed remarkable progress in our understanding of ageing. From an evolutionary standpoint it is generally accepted that ageing is a non-adaptive process which is underscored by a decrease in the force of natural selection with time. From a mechanistic perspective ageing is characterized by a wide variety of cellular mechanisms, including processes such as cellular senescence, telomere attrition, oxidative damage, molecular chaperone activity, and the regulation of biochemical pathways by sirtuins. These biological findings have been accompanied by an unrelenting rise in both life expectancy and the number of older people globally. However, despite age being recognized demographically as a risk factor for healthspan, the processes associated with ageing are routinely overlooked in disease mechanisms. Thus, a central goal of biogerontology is to understand how diseases such as cardiovascular disease (CVD) are shaped by ageing. This challenge cannot be ignored because CVD is the main cause of morbidity in older people. A worthwhile way to examine how ageing intersects with CVD is to consider the effects ageing has on cholesterol metabolism, because dysregualted cholesterol metabolism is the key factor which underpins the pathology of CVD. The aim of this chapter is to outline a hypothesis which accounts for how ageing intersects with intracellular cholesterol metabolism. Moreover, we discuss the implications of this relationship for the onset of disease in the 'oldest old' (individuals ≥85 years of age). We conclude the chapter by discussing the important role mathematical modelling has to play in improving our understanding of cholesterol metabolism and ageing.
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Sulaimanov N, Klose M, Busch H, Boerries M. Understanding the mTOR signaling pathway via mathematical modeling. WILEY INTERDISCIPLINARY REVIEWS. SYSTEMS BIOLOGY AND MEDICINE 2017; 9:e1379. [PMID: 28186392 PMCID: PMC5573916 DOI: 10.1002/wsbm.1379] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 11/09/2016] [Accepted: 12/07/2016] [Indexed: 12/12/2022]
Abstract
The mechanistic target of rapamycin (mTOR) is a central regulatory pathway that integrates a variety of environmental cues to control cellular growth and homeostasis by intricate molecular feedbacks. In spite of extensive knowledge about its components, the molecular understanding of how these function together in space and time remains poor and there is a need for Systems Biology approaches to perform systematic analyses. In this work, we review the recent progress how the combined efforts of mathematical models and quantitative experiments shed new light on our understanding of the mTOR signaling pathway. In particular, we discuss the modeling concepts applied in mTOR signaling, the role of multiple feedbacks and the crosstalk mechanisms of mTOR with other signaling pathways. We also discuss the contribution of principles from information and network theory that have been successfully applied in dissecting design principles of the mTOR signaling network. We finally propose to classify the mTOR models in terms of the time scale and network complexity, and outline the importance of the classification toward the development of highly comprehensive and predictive models. WIREs Syst Biol Med 2017, 9:e1379. doi: 10.1002/wsbm.1379 For further resources related to this article, please visit the WIREs website.
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Affiliation(s)
- Nurgazy Sulaimanov
- Department of Electrical Engineering and Information TechnologyTechnische Universität DarmstadtDarmstadtGermany
- Department of BiologyTechnische Universitat DarmstadtDarmstadtGermany
| | - Martin Klose
- Systems Biology of the Cellular Microenvironment at the DKFZ Partner Site Freiburg ‐ Member of the German Cancer Consortium, Institute of Molecular Medicine and Cell ResearchAlbert‐Ludwigs‐University FreiburgFreiburgGermany and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Hauke Busch
- Systems Biology of the Cellular Microenvironment at the DKFZ Partner Site Freiburg ‐ Member of the German Cancer Consortium, Institute of Molecular Medicine and Cell ResearchAlbert‐Ludwigs‐University FreiburgFreiburgGermany and German Cancer Research Center (DKFZ), Heidelberg, Germany
| | - Melanie Boerries
- Systems Biology of the Cellular Microenvironment at the DKFZ Partner Site Freiburg ‐ Member of the German Cancer Consortium, Institute of Molecular Medicine and Cell ResearchAlbert‐Ludwigs‐University FreiburgFreiburgGermany and German Cancer Research Center (DKFZ), Heidelberg, Germany
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11
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Mc Auley MT, Mooney KM. LDL-C levels in older people: Cholesterol homeostasis and the free radical theory of ageing converge. Med Hypotheses 2017; 104:15-19. [PMID: 28673574 DOI: 10.1016/j.mehy.2017.05.013] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 05/10/2017] [Accepted: 05/15/2017] [Indexed: 01/11/2023]
Abstract
The cardiovascular disease (CVD) risk factor, low density lipoprotein cholesterol (LDL-C) increases with age, up until the midpoint of life in males and females. However, LDL-C can decrease with age in older men and women. Intriguingly, a recent systematic review also revealed an inverse association between LDL-C levels and cardiovascular mortality in older people; low levels of LDL-C were associated with reduced risk of mortality. Such findings are puzzling and require a biological explanation. In this paper a hypothesis is proposed to explain these observations. We hypothesize that the free radical theory of ageing (FRTA) together with disrupted cholesterol homeostasis can account for these observations. Based on this hypothesis, dysregulated hepatic cholesterol homeostasis in older people is characterised by two distinct metabolic states. The first state accounts for an older person who has elevated plasma LDL-C. This state is underpinned by the FRTA which suggests there is a decrease in cellular antioxidant capacity with age. This deficiency enables hepatic reactive oxidative species (ROS) to induce the total activation of HMG-CoA reductase, the key rate limiting enzyme in cholesterol biosynthesis. An increase in cholesterol synthesis elicits a corresponding rise in LDL-C, due to the downregulation of LDL receptor synthesis, and increased production of very low density lipoprotein cholesterol (VLDL-C). In the second state of dysregulation, ROS also trigger the total activation of HMG-CoA reductase. However, due to an age associated decrease in the activity of cholesterol-esterifying enzyme, acyl CoA: cholesterol acyltransferase, there is restricted conversion of excess free cholesterol (FC) to cholesterol esters. Consequently, the secretion of VLDL-C drops, and there is a corresponding decrease in LDL-C. As intracellular levels of FC accumulate, this state progresses to a pathophysiological condition akin to nonalcoholic fatty liver disease. It is our conjecture this deleterious state has the potential to account for the inverse association between LDL-C level and CVD risk observed in older people.
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Affiliation(s)
- Mark T Mc Auley
- Faculty of Science and Engineering, Thornton Science Park, University of Chester, CH2 4NU, UK.
| | - Kathleen M Mooney
- Faculty of Health and Social Care, Edge Hill University, Ormskirk, Lancashire L39 4QP, UK
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12
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Mc Auley MT, Guimera AM, Hodgson D, Mcdonald N, Mooney KM, Morgan AE, Proctor CJ. Modelling the molecular mechanisms of aging. Biosci Rep 2017; 37:BSR20160177. [PMID: 28096317 PMCID: PMC5322748 DOI: 10.1042/bsr20160177] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 12/15/2016] [Accepted: 01/16/2017] [Indexed: 01/09/2023] Open
Abstract
The aging process is driven at the cellular level by random molecular damage that slowly accumulates with age. Although cells possess mechanisms to repair or remove damage, they are not 100% efficient and their efficiency declines with age. There are many molecular mechanisms involved and exogenous factors such as stress also contribute to the aging process. The complexity of the aging process has stimulated the use of computational modelling in order to increase our understanding of the system, test hypotheses and make testable predictions. As many different mechanisms are involved, a wide range of models have been developed. This paper gives an overview of the types of models that have been developed, the range of tools used, modelling standards and discusses many specific examples of models that have been grouped according to the main mechanisms that they address. We conclude by discussing the opportunities and challenges for future modelling in this field.
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Affiliation(s)
- Mark T Mc Auley
- Faculty of Science and Engineering, University of Chester, Chester, U.K
| | - Alvaro Martinez Guimera
- MRC/Arthritis Research UK Centre for Musculoskeletal Ageing (CIMA), Newcastle University, Newcastle upon Tyne, Ormskirk, U.K
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, U.K
| | - David Hodgson
- MRC/Arthritis Research UK Centre for Musculoskeletal Ageing (CIMA), Newcastle University, Newcastle upon Tyne, Ormskirk, U.K
- Musculoskeletal Research Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, U.K
| | - Neil Mcdonald
- MRC/Arthritis Research UK Centre for Musculoskeletal Ageing (CIMA), Newcastle University, Newcastle upon Tyne, Ormskirk, U.K
- Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, U.K
| | | | - Amy E Morgan
- Faculty of Science and Engineering, University of Chester, Chester, U.K
| | - Carole J Proctor
- MRC/Arthritis Research UK Centre for Musculoskeletal Ageing (CIMA), Newcastle University, Newcastle upon Tyne, Ormskirk, U.K.
- Musculoskeletal Research Group, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne, U.K
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Abstract
CVD accounted for 27 % of all deaths in the UK in 2014, and was responsible for 1·7 million hospital admissions in 2013/2014. This condition becomes increasingly prevalent with age, affecting 34·1 and 29·8 % of males and females over 75 years of age respectively in 2011. The dysregulation of cholesterol metabolism with age, often observed as a rise in LDL-cholesterol, has been associated with the pathogenesis of CVD. To compound this problem, it is estimated by 2050, 22 % of the world's population will be over 60 years of age, in culmination with a growing resistance and intolerance to pre-existing cholesterol regulating drugs such as statins. Therefore, it is apparent research into additional therapies for hypercholesterolaemia and CVD prevention is a growing necessity. However, it is also imperative to recognise this complex biological system cannot be studied using a reductionist approach; rather its biological uniqueness necessitates a more integrated methodology, such as that offered by systems biology. In this review, we firstly discuss cholesterol metabolism and how it is affected by diet and the ageing process. Next, we describe therapeutic strategies for hypercholesterolaemia, and finally how the systems biology paradigm can be utilised to investigate how ageing interacts with complex systems such as cholesterol metabolism. We conclude by emphasising the need for nutritionists to work in parallel with the systems biology community, to develop novel approaches to studying cholesterol metabolism and its interaction with ageing.
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Morgan A, Mooney K, Wilkinson S, Pickles N, Mc Auley M. Cholesterol metabolism: A review of how ageing disrupts the biological mechanisms responsible for its regulation. Ageing Res Rev 2016; 27:108-124. [PMID: 27045039 DOI: 10.1016/j.arr.2016.03.008] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Revised: 03/22/2016] [Accepted: 03/30/2016] [Indexed: 02/06/2023]
Abstract
Cholesterol plays a vital role in the human body as a precursor of steroid hormones and bile acids, in addition to providing structure to cell membranes. Whole body cholesterol metabolism is maintained by a highly coordinated balancing act between cholesterol ingestion, synthesis, absorption, and excretion. The aim of this review is to discuss how ageing interacts with these processes. Firstly, we will present an overview of cholesterol metabolism. Following this, we discuss how the biological mechanisms which underpin cholesterol metabolism are effected by ageing. Included in this discussion are lipoprotein dynamics, cholesterol absorption/synthesis and the enterohepatic circulation/synthesis of bile acids. Moreover, we discuss the role of oxidative stress in the pathological progression of atherosclerosis and also discuss how cholesterol biosynthesis is effected by both the mammalian target of rapamycin and sirtuin pathways. Next, we examine how diet and alterations to the gut microbiome can be used to mitigate the impact ageing has on cholesterol metabolism. We conclude by discussing how mathematical models of cholesterol metabolism can be used to identify therapeutic interventions.
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Mooney KM, Morgan AE, Mc Auley MT. Aging and computational systems biology. WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2016; 8:123-39. [PMID: 26825379 DOI: 10.1002/wsbm.1328] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 12/15/2015] [Accepted: 12/29/2015] [Indexed: 12/11/2022]
Abstract
Aging research is undergoing a paradigm shift, which has led to new and innovative methods of exploring this complex phenomenon. The systems biology approach endeavors to understand biological systems in a holistic manner, by taking account of intrinsic interactions, while also attempting to account for the impact of external inputs, such as diet. A key technique employed in systems biology is computational modeling, which involves mathematically describing and simulating the dynamics of biological systems. Although a large number of computational models have been developed in recent years, these models have focused on various discrete components of the aging process, and to date no model has succeeded in completely representing the full scope of aging. Combining existing models or developing new models may help to address this need and in so doing could help achieve an improved understanding of the intrinsic mechanisms which underpin aging.
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Affiliation(s)
- Kathleen M Mooney
- Faculty of Health and Social care, Edge Hill University, Lancashire, UK
| | - Amy E Morgan
- Faculty of Science and Engineering, University of Chester, Chester, UK
| | - Mark T Mc Auley
- Faculty of Science and Engineering, University of Chester, Chester, UK
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Boonekamp JJ, Briga M, Verhulst S. The heuristic value of redundancy models of aging. Exp Gerontol 2015; 71:95-102. [PMID: 26362219 DOI: 10.1016/j.exger.2015.09.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 09/03/2015] [Accepted: 09/04/2015] [Indexed: 11/18/2022]
Abstract
Molecular studies of aging aim to unravel the cause(s) of aging bottom-up, but linking these mechanisms to organismal level processes remains a challenge. We propose that complementary top-down data-directed modelling of organismal level empirical findings may contribute to developing these links. To this end, we explore the heuristic value of redundancy models of aging to develop a deeper insight into the mechanisms causing variation in senescence and lifespan. We start by showing (i) how different redundancy model parameters affect projected aging and mortality, and (ii) how variation in redundancy model parameters relates to variation in parameters of the Gompertz equation. Lifestyle changes or medical interventions during life can modify mortality rate, and we investigate (iii) how interventions that change specific redundancy parameters within the model affect subsequent mortality and actuarial senescence. Lastly, as an example of data-directed modelling and the insights that can be gained from this, (iv) we fit a redundancy model to mortality patterns observed by Mair et al. (2003; Science 301: 1731-1733) in Drosophila that were subjected to dietary restriction and temperature manipulations. Mair et al. found that dietary restriction instantaneously reduced mortality rate without affecting aging, while temperature manipulations had more transient effects on mortality rate and did affect aging. We show that after adjusting model parameters the redundancy model describes both effects well, and a comparison of the parameter values yields a deeper insight in the mechanisms causing these contrasting effects. We see replacement of the redundancy model parameters by more detailed sub-models of these parameters as a next step in linking demographic patterns to underlying molecular mechanisms.
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Affiliation(s)
- Jelle J Boonekamp
- Groningen Institute for Evolutionary Life Sciences University of Groningen P.O. Box 11103, 9700CC Groningen, The Netherlands.
| | - Michael Briga
- Groningen Institute for Evolutionary Life Sciences University of Groningen P.O. Box 11103, 9700CC Groningen, The Netherlands
| | - Simon Verhulst
- Groningen Institute for Evolutionary Life Sciences University of Groningen P.O. Box 11103, 9700CC Groningen, The Netherlands.
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