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Suri A, Hu KKY, Younas T, Dumsday G, Haritos VS. Functionalizing Yeast Lipid Droplets as Versatile Biomaterials. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2308463. [PMID: 38566530 DOI: 10.1002/smll.202308463] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 01/02/2024] [Indexed: 04/04/2024]
Abstract
Lipid droplets (LD) are dynamic cellular organelles of ≈1 µm diameter in yeast where a neutral lipid core is surrounded by a phospholipid monolayer and attendant proteins. Beyond the storage of lipids, opportunities for LD engineering remain underdeveloped but they show excellent potential as new biomaterials. In this research, LD from yeast Saccharomyces cerevisiae is engineered to display mCherry fluorescent protein, Halotag ligand binding protein, plasma membrane binding v-SNARE protein, and carbonic anhydrase enzyme via linkage to oleosin, an LD anchoring protein. Each protein-oleosin fusion is coded via a single gene construct. The expressed fusion proteins are specifically displayed on LD and their functions can be assessed within cells by fluorescence confocal microscopy, TEM, and as isolated materials via AFM, flow cytometry, spectrophotometry, and by enzyme activity assay. LD isolated from the cell are shown to be robust and stabilize proteins anchored into them. These engineered LD function as reporters, bind specific ligands, guide LD and their attendant proteins into union with the plasma membrane, and catalyze reactions. Here, engineered LD functions are extended well beyond traditional lipid storage toward new material applications aided by a versatile oleosin platform anchored into LD and displaying linked proteins.
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Affiliation(s)
- Ankita Suri
- Department of Chemical and Biological Engineering, Monash University, Clayton, 3800, Australia
- CSIRO Black Mountain, 2-40 Clunies Ross Street, Acton, ACT, 2601, Australia
| | - Kevin K Y Hu
- Department of Chemical and Biological Engineering, Monash University, Clayton, 3800, Australia
| | - Tayyaba Younas
- Department of Chemical and Biological Engineering, Monash University, Clayton, 3800, Australia
| | - Geoff Dumsday
- CSIRO Clayton, Research Way, Clayton, Victoria, 3168, Australia
| | - Victoria S Haritos
- Department of Chemical and Biological Engineering, Monash University, Clayton, 3800, Australia
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2
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Kovacs M, Geltinger F, Schartel L, Pöschl S, Briza P, Paschinger M, Boros K, Felder TK, Wimmer H, Duschl J, Rinnerthaler M. Ola1p trafficking indicates an interaction network between mitochondria, lipid droplets, and stress granules in times of stress. J Lipid Res 2023; 64:100473. [PMID: 37949369 PMCID: PMC10757043 DOI: 10.1016/j.jlr.2023.100473] [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: 07/03/2023] [Revised: 09/25/2023] [Accepted: 11/01/2023] [Indexed: 11/12/2023] Open
Abstract
Protein aggregates arise naturally under normal physiological conditions, but their formation is accelerated by age or stress-induced protein misfolding. When the stressful event dissolves, these aggregates are removed by mechanisms, such as aggrephagy, chaperone-mediated autophagy, refolding attempts, or the proteasome. It was recently shown that mitochondria in yeast cells may support these primarily cytosolic processes. Protein aggregates attach to mitochondria, and misfolded proteins are transported into the matrix and degraded by mitochondria-specific proteases. Using a proximity labeling method and colocalization with an established stress granule (SG) marker, we were able to show that these mitochondria-localized aggregates that harbor the "super aggregator" Ola1p are, in fact, SGs. Our in vivo and in vitro studies have revealed that Ola1p can be transferred from mitochondria to lipid droplets (LDs). This "mitochondria to LD" aggregate transfer dampens proteotoxic effects. The LD-based protein aggregate removal system gains importance when other proteolytic systems fail. Furthermore, we were able to show that the distribution of SGs is drastically altered in LD-deficient yeast cells, demonstrating that LDs play a role in the SG life cycle.
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Affiliation(s)
- Melanie Kovacs
- Department of Biosciences, Paris-Lodron University Salzburg, Salzburg, Austria
| | - Florian Geltinger
- Department of Biosciences, Paris-Lodron University Salzburg, Salzburg, Austria; Institute of Functional Anatomy, Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, Berlin, Germany
| | - Lukas Schartel
- Department of Biosciences, Paris-Lodron University Salzburg, Salzburg, Austria; Biocentre, Departments of Biology and Chemistry, Johannes Gutenberg University and Institute of Molecular Biology, Mainz, Germany
| | - Simon Pöschl
- Department of Biosciences, Paris-Lodron University Salzburg, Salzburg, Austria
| | - Peter Briza
- Department of Biosciences, Paris-Lodron University Salzburg, Salzburg, Austria
| | - Manuel Paschinger
- Department of Biosciences, Paris-Lodron University Salzburg, Salzburg, Austria
| | - Kitti Boros
- Department of Biosciences, Paris-Lodron University Salzburg, Salzburg, Austria
| | - Thomas Klaus Felder
- Department of Laboratory Medicine, Paracelsus Medical University, Salzburg, Austria
| | - Herbert Wimmer
- Department of Biosciences, Paris-Lodron University Salzburg, Salzburg, Austria
| | - Jutta Duschl
- Department of Biosciences, Paris-Lodron University Salzburg, Salzburg, Austria
| | - Mark Rinnerthaler
- Department of Biosciences, Paris-Lodron University Salzburg, Salzburg, Austria.
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3
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Mouton SN, Boersma AJ, Veenhoff LM. A physicochemical perspective on cellular ageing. Trends Biochem Sci 2023; 48:949-962. [PMID: 37716870 DOI: 10.1016/j.tibs.2023.08.007] [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: 04/21/2023] [Revised: 08/17/2023] [Accepted: 08/18/2023] [Indexed: 09/18/2023]
Abstract
Cellular ageing described at the molecular level is a multifactorial process that leads to a spectrum of ageing trajectories. There has been recent discussion about whether a decline in physicochemical homeostasis causes aberrant phase transitions, which are a driver of ageing. Indeed, the function of all biological macromolecules, regardless of their participation in biomolecular condensates, depends on parameters such as pH, crowding, and redox state. We expand on the physicochemical homeostasis hypothesis and summarise recent evidence that the intracellular milieu influences molecular processes involved in ageing.
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Affiliation(s)
- Sara N Mouton
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
| | - Arnold J Boersma
- Cellular Protein Chemistry, Bijvoet Centre for Biomolecular Research, Faculty of Science, Utrecht University, Utrecht, The Netherlands
| | - Liesbeth M Veenhoff
- European Research Institute for the Biology of Ageing, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
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Gulias JF, Niesi F, Arán M, Correa-García S, Bermúdez-Moretti M. Gcn4 impacts metabolic fluxes to promote yeast chronological lifespan. PLoS One 2023; 18:e0292949. [PMID: 37831681 PMCID: PMC10575530 DOI: 10.1371/journal.pone.0292949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 10/02/2023] [Indexed: 10/15/2023] Open
Abstract
Aging is characterized by a gradual decline in physiological integrity, which impairs functionality and increases susceptibility to mortality. Dietary restriction, mimicking nutrient scarcity without causing malnutrition, is an intervention known to decelerate the aging process. While various hypotheses have been proposed to elucidate how dietary restriction influences aging, the underlying mechanisms remain incompletely understood. This project aimed to investigate the role of the primary regulator of the general amino acid control (GAAC) pathway, the transcription factor Gcn4, in the aging process of S. cerevisiae cells. Under conditions of amino acid deprivation, which activate Gcn4, the deletion of GCN4 led to a diverse array of physiological changes in the cells. Notably, the absence of Gcn4 resulted in heightened mitochondrial activity, likely contributing to the observed increase in reactive oxygen species (ROS) accumulation. Furthermore, these mutant gcn4Δ cells exhibited reduced ethanol production despite maintaining similar glucose consumption rates, suggesting a pivotal role for Gcn4 in regulating the Crabtree effect. Additionally, there was a marked reduction in trehalose, the storage carbohydrate, within the mutant cells compared to the wild-type strain. The intracellular content of free amino acids also exhibited disparities between the wild-type and GCN4-deficient strains. Taken together, our findings indicate that the absence of GCN4 disrupts cellular homeostasis, triggering significant alterations in interconnected intracellular metabolic pathways. These disruptions have far-reaching metabolic consequences that ultimately culminate in a shortened lifespan.
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Affiliation(s)
- Juan Facundo Gulias
- Facultad de Ciencias Exactas y Naturales, Departamento Química Biológica, Universidad de Buenos Aires, Buenos Aires, Argentina–CONICET, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, Argentina
| | - Florencia Niesi
- Facultad de Ciencias Exactas y Naturales, Departamento Química Biológica, Universidad de Buenos Aires, Buenos Aires, Argentina–CONICET, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, Argentina
| | - Martín Arán
- Fundación Instituto Leloir e Instituto de Investigaciones Bioquímicas de Buenos Aires (IIBBA)—CONICET, Patricias Argentinas, Buenos Aires, Argentina
| | - Susana Correa-García
- Facultad de Ciencias Exactas y Naturales, Departamento Química Biológica, Universidad de Buenos Aires, Buenos Aires, Argentina–CONICET, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, Argentina
| | - Mariana Bermúdez-Moretti
- Facultad de Ciencias Exactas y Naturales, Departamento Química Biológica, Universidad de Buenos Aires, Buenos Aires, Argentina–CONICET, Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales (IQUIBICEN), Buenos Aires, Argentina
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Scrimieri R, Locatelli L, Cazzaniga A, Cazzola R, Malucelli E, Sorrentino A, Iotti S, Maier JA. Ultrastructural features mirror metabolic derangement in human endothelial cells exposed to high glucose. Sci Rep 2023; 13:15133. [PMID: 37704683 PMCID: PMC10499809 DOI: 10.1038/s41598-023-42333-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Accepted: 09/08/2023] [Indexed: 09/15/2023] Open
Abstract
High glucose-induced endothelial dysfunction is the early event that initiates diabetes-induced vascular disease. Here we employed Cryo Soft X-ray Tomography to obtain three-dimensional maps of high D-glucose-treated endothelial cells and their controls at nanometric spatial resolution. We then correlated ultrastructural differences with metabolic rewiring. While the total mitochondrial mass does not change, high D-glucose promotes mitochondrial fragmentation, as confirmed by the modulation of fission-fusion markers, and dysfunction, as demonstrated by the drop of membrane potential, the decreased oxygen consumption and the increased production of reactive oxygen species. The 3D ultrastructural analysis also indicates the accumulation of lipid droplets in cells cultured in high D-glucose. Indeed, because of the decrease of fatty acid β-oxidation induced by high D-glucose concentration, triglycerides are esterified into fatty acids and then stored into lipid droplets. We propose that the increase of lipid droplets represents an adaptive mechanism to cope with the overload of glucose and associated oxidative stress and metabolic dysregulation.
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Affiliation(s)
- Roberta Scrimieri
- Department of Biomedical and Clinical Sciences, Università degli Studi di Milano, 20157, Milan, Italy.
| | - Laura Locatelli
- Department of Biomedical and Clinical Sciences, Università degli Studi di Milano, 20157, Milan, Italy
| | - Alessandra Cazzaniga
- Department of Biomedical and Clinical Sciences, Università degli Studi di Milano, 20157, Milan, Italy
| | - Roberta Cazzola
- Department of Biomedical and Clinical Sciences, Università degli Studi di Milano, 20157, Milan, Italy
| | - Emil Malucelli
- Department of Pharmacy and Biotechnology, Università di Bologna, 40127, Bologna, Italy
| | - Andrea Sorrentino
- Mistral Beamline, ALBA Synchrotron Light Source, Cerdanyola del Valles, 08290, Barcelona, Spain
| | - Stefano Iotti
- Department of Pharmacy and Biotechnology, Università di Bologna, 40127, Bologna, Italy
- National Institute of Biostructures and Biosystems, Viale Delle Medaglie d'Oro 305, 00136, Rome, Italy
| | - Jeanette A Maier
- Department of Biomedical and Clinical Sciences, Università degli Studi di Milano, 20157, Milan, Italy.
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Bresgen N, Kovacs M, Lahnsteiner A, Felder TK, Rinnerthaler M. The Janus-Faced Role of Lipid Droplets in Aging: Insights from the Cellular Perspective. Biomolecules 2023; 13:912. [PMID: 37371492 DOI: 10.3390/biom13060912] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 05/22/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
It is widely accepted that nine hallmarks-including mitochondrial dysfunction, epigenetic alterations, and loss of proteostasis-exist that describe the cellular aging process. Adding to this, a well-described cell organelle in the metabolic context, namely, lipid droplets, also accumulates with increasing age, which can be regarded as a further aging-associated process. Independently of their essential role as fat stores, lipid droplets are also able to control cell integrity by mitigating lipotoxic and proteotoxic insults. As we will show in this review, numerous longevity interventions (such as mTOR inhibition) also lead to strong accumulation of lipid droplets in Saccharomyces cerevisiae, Caenorhabditis elegans, Drosophila melanogaster, and mammalian cells, just to name a few examples. In mammals, due to the variety of different cell types and tissues, the role of lipid droplets during the aging process is much more complex. Using selected diseases associated with aging, such as Alzheimer's disease, Parkinson's disease, type II diabetes, and cardiovascular disease, we show that lipid droplets are "Janus"-faced. In an early phase of the disease, lipid droplets mitigate the toxicity of lipid peroxidation and protein aggregates, but in a later phase of the disease, a strong accumulation of lipid droplets can cause problems for cells and tissues.
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Affiliation(s)
- Nikolaus Bresgen
- Department of Biosciences and Medical Biology, Paris-Lodron University Salzburg, 5020 Salzburg, Austria
| | - Melanie Kovacs
- Department of Biosciences and Medical Biology, Paris-Lodron University Salzburg, 5020 Salzburg, Austria
| | - Angelika Lahnsteiner
- Department of Biosciences and Medical Biology, Paris-Lodron University Salzburg, 5020 Salzburg, Austria
| | - Thomas Klaus Felder
- Department of Laboratory Medicine, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Mark Rinnerthaler
- Department of Biosciences and Medical Biology, Paris-Lodron University Salzburg, 5020 Salzburg, Austria
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7
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Locatelli L, Fedele G, Maier JA. The Role of Txnip in Mediating Low-Magnesium-Driven Endothelial Dysfunction. Int J Mol Sci 2023; 24:ijms24098351. [PMID: 37176057 PMCID: PMC10179684 DOI: 10.3390/ijms24098351] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 04/28/2023] [Accepted: 05/04/2023] [Indexed: 05/15/2023] Open
Abstract
Magnesium deficiency is associated with a greater risk of developing cardiovascular diseases since this cation is fundamental in regulating vascular function. This clinical evidence is sustained by in vitro studies showing that culturing endothelial cells in low concentrations of magnesium promotes the acquisition of a pro-oxidant and pro-inflammatory phenotype. Here, we show that the increase in reactive oxygen species in endothelial cells in low-magnesium-containing medium is due to the upregulation of the pro-oxidant protein thioredoxin interacting protein (TXNIP), with a consequent accumulation of lipid droplets and increase in endothelial permeability through the downregulation and relocalization of junctional proteins. Silencing TXNIP restores the endothelial barrier and lipid content. Because (i) mitochondria serve multiple roles in shaping cell function, health and survival and (ii) mitochondria are the main intracellular stores of magnesium, it is of note that no significant alterations were detected in their morphology and dynamics in our experimental model. We conclude that TXNIP upregulation contributes to low-magnesium-induced endothelial dysfunction in vitro.
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Affiliation(s)
- Laura Locatelli
- Department of Biomedical and Clinical Sciences, Università di Milano, Via GB Grassi 74, 20157 Milano, Italy
| | - Giorgia Fedele
- Department of Biomedical and Clinical Sciences, Università di Milano, Via GB Grassi 74, 20157 Milano, Italy
| | - Jeanette A Maier
- Department of Biomedical and Clinical Sciences, Università di Milano, Via GB Grassi 74, 20157 Milano, Italy
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8
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Deb R, Nagotu S. The nexus between peroxisome abundance and chronological ageing in Saccharomyces cerevisiae. Biogerontology 2023; 24:81-97. [PMID: 36209442 DOI: 10.1007/s10522-022-09992-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Accepted: 09/23/2022] [Indexed: 01/20/2023]
Abstract
Ageing is characterized by changes in several cellular processes, with dysregulation of peroxisome function being one of them. Interestingly, the most conserved function of peroxisomes, ROS homeostasis, is strongly associated with ageing and age-associated pathologies. Previous studies have identified a role for peroxisomes in the regulation of chronological lifespan in yeast. In this study, we report the effect of altered peroxisome number on the chronological lifespan of yeast in two different growth media conditions. Three mutants, pex11, pex25 and pex27, defective in peroxisome fission, have been thoroughly investigated for the chronological lifespan. Reduced chronological lifespan of all the mutants was observed in peroxisome-inducing growth conditions. Furthermore, the combined deletion pex11pex25 exhibited the most prominent reduction in lifespan. Interestingly altered peroxisomal phenotype upon ageing was observed in all the cells. Increased ROS accumulation and reduced catalase activity was exhibited by chronologically aged mutant cells. Interestingly, mutants with reduced number of peroxisomes concomitantly also exhibited an accumulation of free fatty acids and increased number of lipid droplets. Taken together, our results reveal a previously unrealized effect of fission proteins in the chronological lifespan of yeast.
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Affiliation(s)
- Rachayeeta Deb
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India
| | - Shirisha Nagotu
- Organelle Biology and Cellular Ageing Lab, Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati, Assam, 781039, India.
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Picca A, Guerra F, Calvani R, Romano R, Coelho-Junior HJ, Damiano FP, Bucci C, Marzetti E. Circulating Mitochondrial DNA and Inter-Organelle Contact Sites in Aging and Associated Conditions. Cells 2022; 11:cells11040675. [PMID: 35203322 PMCID: PMC8870554 DOI: 10.3390/cells11040675] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/11/2022] [Accepted: 02/14/2022] [Indexed: 02/07/2023] Open
Abstract
Mitochondria are primarily involved in cell bioenergetics, regulation of redox homeostasis, and cell death/survival signaling. An immunostimulatory property of mitochondria has also been recognized which is deployed through the extracellular release of entire or portioned organelle and/or mitochondrial DNA (mtDNA) unloading. Dynamic homo- and heterotypic interactions involving mitochondria have been described. Each type of connection has functional implications that eventually optimize mitochondrial activity according to the bioenergetic demands of a specific cell/tissue. Inter-organelle communications may also serve as molecular platforms for the extracellular release of mitochondrial components and subsequent ignition of systemic inflammation. Age-related chronic inflammation (inflamm-aging) has been associated with mitochondrial dysfunction and increased extracellular release of mitochondrial components—in particular, cell-free mtDNA. The close relationship between mitochondrial dysfunction and cellular senescence further supports the central role of mitochondria in the aging process and its related conditions. Here, we provide an overview of (1) the mitochondrial genetic system and the potential routes for generating and releasing mtDNA intermediates; (2) the pro-inflammatory pathways elicited by circulating mtDNA; (3) the participation of inter-organelle contacts to mtDNA homeostasis; and (4) the link of these processes with senescence and age-associated conditions.
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Affiliation(s)
- Anna Picca
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, 00168 Rome, Italy; (A.P.); (F.P.D.); (E.M.)
| | - Flora Guerra
- Department of Biological and Environmental Sciences and Technologies, Università del Salento, 73100 Lecce, Italy; (F.G.); (R.R.); (C.B.)
| | - Riccardo Calvani
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, 00168 Rome, Italy; (A.P.); (F.P.D.); (E.M.)
- Correspondence: ; Tel.: +39-06-3015-5559; Fax: +39-06-3051-911
| | - Roberta Romano
- Department of Biological and Environmental Sciences and Technologies, Università del Salento, 73100 Lecce, Italy; (F.G.); (R.R.); (C.B.)
| | - Hélio José Coelho-Junior
- Department of Geriatrics and Orthopedics, Università Cattolica del Sacro Cuore, 00168 Rome, Italy;
| | - Francesco P. Damiano
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, 00168 Rome, Italy; (A.P.); (F.P.D.); (E.M.)
| | - Cecilia Bucci
- Department of Biological and Environmental Sciences and Technologies, Università del Salento, 73100 Lecce, Italy; (F.G.); (R.R.); (C.B.)
| | - Emanuele Marzetti
- Fondazione Policlinico Universitario “Agostino Gemelli” IRCCS, 00168 Rome, Italy; (A.P.); (F.P.D.); (E.M.)
- Department of Geriatrics and Orthopedics, Università Cattolica del Sacro Cuore, 00168 Rome, Italy;
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