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Coen PM, Huo Z, Tranah GJ, Barnes HN, Zhang X, Wolff CA, Wu K, Cawthon PM, Hepple RT, Toledo FGS, Evans DS, Santiago‐Fernández O, Cuervo AM, Kritchevsky SB, Newman AB, Cummings SR, Esser KA. Autophagy gene expression in skeletal muscle of older individuals is associated with physical performance, muscle volume and mitochondrial function in the study of muscle, mobility and aging (SOMMA). Aging Cell 2024; 23:e14118. [PMID: 38627910 PMCID: PMC11166359 DOI: 10.1111/acel.14118] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 01/14/2024] [Accepted: 02/02/2024] [Indexed: 04/30/2024] Open
Abstract
Autophagy is essential for proteostasis, energetic balance, and cell defense and is a key pathway in aging. Identifying associations between autophagy gene expression patterns in skeletal muscle and physical performance outcomes would further our knowledge of mechanisms related with proteostasis and healthy aging. Muscle biopsies were obtained from participants in the Study of Muscle, Mobility, and Aging (SOMMA). For 575 participants, RNA was sequenced and expression of 281 genes related to autophagy regulation, mitophagy, and mTOR/upstream pathways was determined. Associations between gene expression and outcomes including mitochondrial respiration in muscle fiber bundles (MAX OXPHOS), physical performance (VO2 peak, 400 m walking speed, and leg power), and thigh muscle volume, were determined using negative binomial regression models. For autophagy, key transcriptional regulators including TFE3 and NFKB-related genes (RELA, RELB, and NFKB1) were negatively associated with outcomes. On the contrary, regulators of oxidative metabolism that also promote overall autophagy, mitophagy, and pexophagy (PPARGC1A, PPARA, and EPAS1) were positively associated with multiple outcomes. In line with this, several mitophagy, fusion, and fission-related genes (NIPSNAP2, DNM1L, and OPA1) were also positively associated with outcomes. For mTOR pathway and related genes, expression of WDR59 and WDR24, both subunits of GATOR2 complex (an indirect inhibitor of mTORC1), and PRKAG3, which is a regulatory subunit of AMPK, were negatively correlated with multiple outcomes. Our study identifies autophagy and selective autophagy such as mitophagy gene expression patterns in human skeletal muscle related to physical performance, muscle volume, and mitochondrial function in older persons which may lead to target identification to preserve mobility and independence.
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Affiliation(s)
- Paul M. Coen
- Translational Research Institute, AdventHealthOrlandoFloridaUSA
| | - Zhiguang Huo
- Department of Biostatistics, College of Public Health & Health ProfessionsCollege of Medicine University of FloridaGainesvilleFloridaUSA
| | - Gregory J. Tranah
- California Pacific Medical Center Research InstituteSan FranciscoCaliforniaUSA
| | - Haley N. Barnes
- California Pacific Medical Center Research InstituteSan FranciscoCaliforniaUSA
| | - Xiping Zhang
- Department of Physiology and Aging, College of MedicineUniversity of FloridaGainesvilleFloridaUSA
| | - Christopher A. Wolff
- Department of Physiology and Aging, College of MedicineUniversity of FloridaGainesvilleFloridaUSA
| | - Kevin Wu
- Department of Physiology and Aging, College of MedicineUniversity of FloridaGainesvilleFloridaUSA
| | - Peggy M. Cawthon
- California Pacific Medical Center Research InstituteSan FranciscoCaliforniaUSA
- Department of Epidemiology and BiostatisticsUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - Russell T. Hepple
- Department of Physical TherapyUniversity of FloridaGainesvilleFloridaUSA
| | - Frederico G. S. Toledo
- Department of Medicine, Division of Endocrinology and MetabolismUniversity of Pittsburgh School of MedicinePittsburghPennsylvaniaUSA
| | - Daniel S. Evans
- California Pacific Medical Center Research InstituteSan FranciscoCaliforniaUSA
- Department of Epidemiology and BiostatisticsUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - Olaya Santiago‐Fernández
- Department of Developmental & Molecular BiologyAlbert Einstein College of MedicineNew YorkNew YorkUSA
| | - Ana Maria Cuervo
- Department of Developmental & Molecular BiologyAlbert Einstein College of MedicineNew YorkNew YorkUSA
| | - Stephen B. Kritchevsky
- Department of Internal MedicineWake Forest University School of MedicineWinston‐SalemNorth CarolinaUSA
| | - Anne B. Newman
- Department of Epidemiology, School of Public HealthUniversity of PittsburghPittsburghPennsylvaniaUSA
| | - Steven R. Cummings
- California Pacific Medical Center Research InstituteSan FranciscoCaliforniaUSA
- Department of Epidemiology and BiostatisticsUniversity of California San FranciscoSan FranciscoCaliforniaUSA
| | - Karyn A. Esser
- Department of Physiology and Aging, College of MedicineUniversity of FloridaGainesvilleFloridaUSA
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2
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Oliveira AN, Memme JM, Wong J, Hood DA. Dimorphic effect of TFE3 in determining mitochondrial and lysosomal content in muscle following denervation. Skelet Muscle 2024; 14:7. [PMID: 38643162 PMCID: PMC11031958 DOI: 10.1186/s13395-024-00339-1] [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: 10/11/2023] [Accepted: 03/17/2024] [Indexed: 04/22/2024] Open
Abstract
BACKGROUND Muscle atrophy is a common consequence of the loss of innervation and is accompanied by mitochondrial dysfunction. Mitophagy is the adaptive process through which damaged mitochondria are removed via the lysosomes, which are regulated in part by the transcription factor TFE3. The role of lysosomes and TFE3 are poorly understood in muscle atrophy, and the effect of biological sex is widely underreported. METHODS Wild-type (WT) mice, along with mice lacking TFE3 (KO), a transcriptional regulator of lysosomal and autophagy-related genes, were subjected to unilateral sciatic nerve denervation for up to 7 days, while the contralateral limb was sham-operated and served as an internal control. A subset of animals was treated with colchicine to capture mitophagy flux. RESULTS WT females exhibited elevated oxygen consumption rates during active respiratory states compared to males, however this was blunted in the absence of TFE3. Females exhibited higher mitophagy flux rates and greater lysosomal content basally compared to males that was independent of TFE3 expression. Following denervation, female mice exhibited less muscle atrophy compared to male counterparts. Intriguingly, this sex-dependent muscle sparing was lost in the absence of TFE3. Denervation resulted in 45% and 27% losses of mitochondrial content in WT and KO males respectively, however females were completely protected against this decline. Decreases in mitochondrial function were more severe in WT females compared to males following denervation, as ROS emission was 2.4-fold higher. In response to denervation, LC3-II mitophagy flux was reduced by 44% in females, likely contributing to the maintenance of mitochondrial content and elevated ROS emission, however this response was dysregulated in the absence of TFE3. While both males and females exhibited increased lysosomal content following denervation, this response was augmented in females in a TFE3-dependent manner. CONCLUSIONS Females have higher lysosomal content and mitophagy flux basally compared to males, likely contributing to the improved mitochondrial phenotype. Denervation-induced mitochondrial adaptations were sexually dimorphic, as females preferentially preserve content at the expense of function, while males display a tendency to maintain mitochondrial function. Our data illustrate that TFE3 is vital for the sex-dependent differences in mitochondrial function, and in determining the denervation-induced atrophy phenotype.
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Affiliation(s)
- Ashley N Oliveira
- School of Kinesiology and Health Science Muscle Health Research Centre, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada
| | - Jonathan M Memme
- School of Kinesiology and Health Science Muscle Health Research Centre, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada
| | - Jenna Wong
- School of Kinesiology and Health Science Muscle Health Research Centre, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada
| | - David A Hood
- School of Kinesiology and Health Science Muscle Health Research Centre, York University, 4700 Keele St, Toronto, ON, M3J 1P3, Canada.
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3
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Wong JC, Oliveira AN, Khemraj P, Hood DA. The role of TFE3 in mediating skeletal muscle mitochondrial adaptations to exercise training. J Appl Physiol (1985) 2024; 136:262-273. [PMID: 38095014 DOI: 10.1152/japplphysiol.00484.2023] [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: 07/17/2023] [Revised: 12/07/2023] [Accepted: 12/11/2023] [Indexed: 01/26/2024] Open
Abstract
Transcription factor E3 (TFE3) is a transcription factor that activates the expression of lysosomal genes involved in the clearance of dysfunctional mitochondria, termed mitophagy. With exercise, TFE3 is presumed to optimize the mitochondrial pool through the removal of organelles via lysosomes. However, the molecular mechanisms of the involved pathways remain unknown. Wild-type (WT) and TFE3 knockout (KO) mice were subjected to 6 wk of voluntary wheel running as an endurance training regimen. This was followed by a 45-min bout of in situ stimulation of the sciatic nerve innervating hindlimb muscles to evaluate muscle fatigue and contractile properties. A subset of animals was treated with colchicine to measure autophagy and mitophagy flux. Fatigability during stimulation was reduced with training in WT animals, as seen by a 13% increase in the percentage of maximum force at 5 min of stimulation, and a 30% increase at 30 minutes. Permeabilized fiber oxygen consumption was also improved with training. Concurrent with improved muscle and mitochondrial function, cytochrome c oxidase (COX) activity and COX I protein expression were increased in trained WT animals compared to untrained animals, signifying an increase in mitochondrial content. These training adaptations were abolished with the loss of TFE3. Surprisingly, the absence of TFE3 did not affect lysosomal content nor did it blunt the induction of mitophagy flux with contractile activity compared to WT mice. Our results suggest that the loss of TFE3 compromises beneficial training adaptations that lead to improved muscle endurance and mitochondrial function.NEW & NOTEWORTHY Our understanding of the role of transcription factor E3 (TFE3) in skeletal muscle is very limited. This research shows that TFE3 plays a direct role in skeletal muscle mitochondrial enhancement with exercise training, thereby introducing a paradigm shift in our perception of the function of TFE3 in mitochondrial maintenance, beyond mitophagy. This research serves to introduce TFE3 as a protein that holds promise as a future therapeutic target for metabolic diseases and skeletal muscle dysfunction.
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Affiliation(s)
- Jenna C Wong
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Ashley N Oliveira
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - Priyanka Khemraj
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
| | - David A Hood
- Muscle Health Research Centre, School of Kinesiology and Health Science, York University, Toronto, Ontario, Canada
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McCormick JJ, McManus MK, King KE, Goulet N, Kenny GP. The intensity-dependent effects of exercise and superimposing environmental heat stress on autophagy in peripheral blood mononuclear cells from older men. Am J Physiol Regul Integr Comp Physiol 2024; 326:R29-R42. [PMID: 37955130 DOI: 10.1152/ajpregu.00163.2023] [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: 06/30/2023] [Revised: 10/31/2023] [Accepted: 11/01/2023] [Indexed: 11/14/2023]
Abstract
Autophagy is a vital cellular process, essential to maintaining cellular function during acute physiological stressors including exercise and heat stress. We previously showed that autophagy occurs during exercise in an intensity-dependent manner in peripheral blood mononuclear cells (PBMCs) from young men, with elevated responses in the heat. However, given autophagy declines with age, it is unclear whether a similar pattern of response occurs in older adults. Therefore, we evaluated autophagy and the cellular stress response [i.e., apoptosis, inflammation, and the heat shock response (HSR)] in PBMCs from 10 healthy older men [mean (SD): aged 70 yr (5)] in response to 30 min of semirecumbent cycling at low, moderate, and vigorous intensities [40, 55, and 70% maximal oxygen consumption (V̇o2max), respectively] in a temperate (25°C) environment, with an additional vigorous-intensity bout (70% of V̇o2max) performed in a hot environment (40°C). Responses were evaluated before and after exercise, as well as throughout a 6-h seated recovery period performed in the same environmental conditions as the respective exercise bout. Proteins were assessed via Western blot. Although we observed elevations in mean body temperature with each increase in exercise intensity, autophagy was only stimulated during vigorous-intensity exercise, where we observed elevations in LC3-II (P < 0.05). However, when the same exercise was performed in the heat, the LC3-II response was attenuated, which was accompanied by significant p62 accumulation (P < 0.05). Altogether, our findings demonstrate that older adults exhibit autophagic impairments when the same vigorous-intensity exercise is performed in hot environments, potentially underlying heat-induced cellular vulnerability in older men.NEW & NOTEWORTHY We demonstrate that autophagic stimulation occurs in response to short-duration (30-min) vigorous-intensity exercise in peripheral blood mononuclear cells from older adults; however, no changes in autophagy occur during low- or moderate-intensity exercise. Moreover, older adults exhibit autophagic impairments when the same vigorous-intensity exercise is performed in hot ambient conditions. When paired with an attenuated heat shock response, as well as elevated apoptotic responses, older men may exhibit greater cellular vulnerability to exertional heat stress.
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Affiliation(s)
- James J McCormick
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Morgan K McManus
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Kelli E King
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Nicholas Goulet
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
| | - Glen P Kenny
- Human and Environmental Physiology Research Unit, School of Human Kinetics, University of Ottawa, Ottawa, Ontario, Canada
- Clinical Epidemiology Program, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
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5
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Chen P, Zhou Z, Sun L, Yu X, Li K, Li J, He M, Zhou X, Luo F, Zhao J, Chen W. Quantitative multi-parameter assessment of age- and gender-related variation of back extensor muscles in healthy adults using Dixon MR imaging. Eur Radiol 2024; 34:69-79. [PMID: 37537425 DOI: 10.1007/s00330-023-09954-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Revised: 04/07/2023] [Accepted: 05/20/2023] [Indexed: 08/05/2023]
Abstract
OBJECTIVES Investigate sex differences in age-related back extensor muscle degeneration using Dixon MRI and analyze the relationship between quantitative muscle parameters and back muscle strength in healthy adults. METHODS 105 healthy subjects underwent lumbar Dixon MRI. Fat fraction (FF), cross-sectional area (CSA), functional CSA (FCSA), and relative FCSA (RFCSA) of multifidus muscle (MF) and erector spinae (ES) were quantified. Back extension muscle strength was measured using an external fixation dynamometer. ANOVA with post hoc Tukey correction was used for age group comparisons. Partial and Spearman's correlation analyzed relationships between age, muscle parameters, and muscle strength. RESULTS MF and ES FF significantly increased with age in both genders (r = 0.55-0.85; p < 0.001). Muscle FF increased prominently for females (40-49 years, MF and 50-59 years, ES) and males (60-73 years, MF and ES). In females, total ES FCSA and RFCSA (r = - 0.42, - 0.37; p < 0.01) correlated with age. While in males, all MF and ES muscle size parameters, except total MF CSA, correlated with age (r = - 0.30 to - 0.58; p < 0.05). Back extension muscle strength correlated with mean FF, total CSA, and total FCAS for MF and ES individually (p < 0.001). The combined MF + ES FCSA correlation coefficient (r = 0.63) was higher than FF (r = - 0.51) and CSA (r = 0.59) (p < 0.001). CONCLUSIONS Age-related back extensor muscle degeneration varies by muscle type and sex. FCSA has the highest association with back muscle strength compared to FF and CSA. CLINICAL RELEVANCE STATEMENT The investigation of sex differences in age-related back extensor muscle degeneration utilizing Dixon imaging may hold significant implications for evaluating spine health and enabling earlier intervention. Muscles' FCSA could contribute to acquiring additional evidence for reflecting muscle function change. KEY POINTS • The multifidus muscle (MF) and erector spinae (ES) fat fraction (FF) increased with age at all lumbar disc levels in females and males. • Age-related changes in muscle morphological quantitative parameters of healthy adults were specific by muscle type and gender. • The muscle functional cross-sectional area (FCSA) measured by Dixon imaging may better monitor back extensor muscle strength changes than muscle FF and cross-sectional area (CSA).
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Affiliation(s)
- Pinzhen Chen
- Department of Radiology, The First Affiliated Hospital, Army Medical University, 30 Gaotanyan Street Shapingba District, Chongqing, 400038, China
| | - Zhou Zhou
- Department of Radiology, The First Affiliated Hospital, Army Medical University, 30 Gaotanyan Street Shapingba District, Chongqing, 400038, China
| | - Li Sun
- Health Management Center, The First Affiliated Hospital, Army Medical University, Chongqing, 400038, China
| | - Xueke Yu
- Department of Orthopedics, The First Affiliated Hospital, Army Medical University, Chongqing, 400038, China
| | - Kai Li
- Department of Orthopedics, The First Affiliated Hospital, Army Medical University, Chongqing, 400038, China
| | - Jin Li
- Department of Radiology, The First Affiliated Hospital, Army Medical University, 30 Gaotanyan Street Shapingba District, Chongqing, 400038, China
| | - Min He
- Department of Radiology, The First Affiliated Hospital, Army Medical University, 30 Gaotanyan Street Shapingba District, Chongqing, 400038, China
| | - Xiaoyue Zhou
- MR Collaboration NEA, Siemens Healthcare Ltd, Shanghai, 201318, China
| | - Fei Luo
- Department of Orthopedics, The First Affiliated Hospital, Army Medical University, Chongqing, 400038, China
| | - Jun Zhao
- Department of Radiology, The First Affiliated Hospital, Army Medical University, 30 Gaotanyan Street Shapingba District, Chongqing, 400038, China.
| | - Wei Chen
- Department of Radiology, The First Affiliated Hospital, Army Medical University, 30 Gaotanyan Street Shapingba District, Chongqing, 400038, China.
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Nuccio A, Nogueira-Ferreira R, Moreira-Pais A, Attanzio A, Duarte JA, Luparello C, Ferreira R. The contribution of mitochondria to age-related skeletal muscle wasting: A sex-specific perspective. Life Sci 2024; 336:122324. [PMID: 38042281 DOI: 10.1016/j.lfs.2023.122324] [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: 09/09/2023] [Revised: 11/27/2023] [Accepted: 11/29/2023] [Indexed: 12/04/2023]
Abstract
As people age, their skeletal muscle (SkM) experiences a decline in mitochondrial functionality and density, which leads to decreased energy production and increased generation of reactive oxygen species. This cascade of events, in turn, might determine the loss of SkM mass, strength and quality. Even though the mitochondrial processes dysregulated by aging, such as oxidative phosphorylation, mitophagy, antioxidant defenses and mtDNA transcription, are the same in both sexes, mitochondria age differently in the SkM of men and women. Indeed, the onset and magnitude of the impairment of these processes seem to be influenced by sex-specific factors. Sexual hormones play a pivotal role in the regulation of SkM mass through both genomic and non-genomic mechanisms. However, the precise mechanisms by which these hormones regulate mitochondrial plasticity in SkM are not fully understood. Although the presence of estrogen receptors in mitochondria is recognized, it remains unclear whether androgen receptors affect mitochondrial function. This comprehensive review critically dissects the current knowledge on the interplay of sex in the aging of SkM, focusing on the role of sex hormones and the corresponding signaling pathways in shaping mitochondrial plasticity. Improved knowledge on the sex dimorphism of mitochondrial aging may lead to sex-tailored interventions that target mitochondrial health, which could be effective in slowing or preventing age-related muscle loss.
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Affiliation(s)
- Alessandro Nuccio
- LAQV/REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, 90128 Palermo, Italy.
| | - Rita Nogueira-Ferreira
- Cardiovascular R&D Center - UnIC@RISE, Department of Surgery and Physiology, Faculty of Medicine of the University of Porto, 4200-319 Porto, Portugal.
| | - Alexandra Moreira-Pais
- LAQV/REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal; Research Center in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sports, University of Porto (FADEUP), Laboratory for Integrative and Translational Research in Population Health (ITR), 4200-450 Porto, Portugal; Centre for Research and Technology of Agro Environmental and Biological Sciences (CITAB), Inov4Agro, University of Trás-os-Montes and Alto Douro (UTAD), Quinta de Prados, 5000-801 Vila Real, Portugal.
| | - Alessandro Attanzio
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, 90128 Palermo, Italy.
| | - José Alberto Duarte
- Research Center in Physical Activity, Health and Leisure (CIAFEL), Faculty of Sports, University of Porto (FADEUP), Laboratory for Integrative and Translational Research in Population Health (ITR), 4200-450 Porto, Portugal; TOXRUN - Toxicology Research Unit, University Institute of Health Sciences, CESPU, CRL, 4585-116 Gandra, Portugal.
| | - Claudio Luparello
- Department of Biological, Chemical and Pharmaceutical Sciences and Technologies (STEBICEF), University of Palermo, 90128 Palermo, Italy.
| | - Rita Ferreira
- LAQV/REQUIMTE, Department of Chemistry, University of Aveiro, 3810-193 Aveiro, Portugal.
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7
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Cooke D, Ables GP. Physical activity of mice on dietary sulfur amino acid restriction is influenced by age of diet initiation and biological sex. Sci Rep 2023; 13:20609. [PMID: 37996548 PMCID: PMC10667228 DOI: 10.1038/s41598-023-47676-7] [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: 02/21/2023] [Accepted: 11/16/2023] [Indexed: 11/25/2023] Open
Abstract
Sulfur amino acid restriction (SAAR)-the reduction of methionine and cysteine concentrations either in the diet or by genetic manipulation-promotes health span and extends lifespan, but its effects on physical activity remain unclear. We investigated whether age of diet initiation and biological sex could influence physical activity in mice fed either a control diet (CF, 0.86% methionine w/w) or SAAR (0.12% methionine w/w). Quadriceps femoris muscle mass is smaller in SAAR than in CF mice. Young mice fed a chronic SAAR diet at 8 weeks of age exhibited improved wire hang and running wheel activities compared to young CF mice, while aged mice showed comparable results. The effects of chronic SAAR on physical activity was mildly influenced by sex as observed in middle-aged male SAAR mice who showed minor improvements than CF males while middle-aged females displayed no discernible effects. Muscle mass is minimally affected by changes in markers of protein synthesis, autophagy and atrophy. Improvements to physical activity in young SAAR mice could be partially attributed to increased skeletal muscle mitochondrial activity. Furthermore, SAAR in C2C12 myotubes increased citrate synthase protein expression and enhanced succinyl dehydrogenase enzyme activity compared to CF myotubes. Overall, our data reveal that SAAR can improve mouse physical activity without compromising muscle proteostasis. This is partially due to enhanced mitochondrial activity, but the effects are influenced by age of diet initiation and sex.
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Affiliation(s)
- Diana Cooke
- Orentreich Foundation for the Advancement of Science, Inc., 855 Route 301, Cold Spring, NY, 10516, USA
| | - Gene P Ables
- Orentreich Foundation for the Advancement of Science, Inc., 855 Route 301, Cold Spring, NY, 10516, USA.
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8
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Yee EM, Hauser CT, Petrocelli JJ, de Hart NMMP, Ferrara PJ, Bombyck P, Fennel ZJ, van Onselen L, Mookerjee S, Funai K, Symons JD, Drummond MJ. Treadmill training does not enhance skeletal muscle recovery following disuse atrophy in older male mice. Front Physiol 2023; 14:1263500. [PMID: 37942230 PMCID: PMC10628510 DOI: 10.3389/fphys.2023.1263500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2023] [Accepted: 10/02/2023] [Indexed: 11/10/2023] Open
Abstract
Introduction: A hallmark of aging is poor muscle recovery following disuse atrophy. Efficacious strategies to enhance muscle recovery following disuse atrophy in aging are non-existent. Prior exercise training could result in favorable muscle morphological and cellular adaptations that may promote muscle recovery in aging. Here, we characterized the impact of exercise training on skeletal muscle inflammatory and metabolic profiles and cellular remodeling and function, together with femoral artery reactivity prior to and following recovery from disuse atrophy in aged male mice. We hypothesized that 12 weeks of treadmill training in aged male mice would improve skeletal muscle cellular remodeling at baseline and during recovery from disuse atrophy, resulting in improved muscle regrowth. Methods: Physical performance, ex vivo muscle and vascular function, tissue and organ mass, hindlimb muscle cellular remodeling (macrophage, satellite cell, capillary, myofiber size, and fibrosis), and proteolytic, inflammatory, and metabolic muscle transcripts were evaluated in aged exercise-trained and sedentary mice. Results: We found that at baseline following exercise training (vs. sedentary mice), exercise capacity and physical function increased, fat mass decreased, and endothelial function improved. However, exercise training did not alter tibialis anterior or gastrocnemius muscle transcriptional profile, macrophage, satellite cell, capillarity or collagen content, or myofiber size and only tended to increase tibialis mass during recovery from disuse atrophy. Conclusion: While exercise training in old male mice improved endothelial function, physical performance, and whole-body tissue composition as anticipated, 12 weeks of treadmill training had limited impact on skeletal muscle remodeling at baseline or in response to recovery following disuse atrophy.
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Affiliation(s)
- Elena M. Yee
- Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, UT, United States
| | - Carson T. Hauser
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, United States
| | - Jonathan J. Petrocelli
- Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, UT, United States
| | - Naomi M. M. P. de Hart
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, United States
| | - Patrick J. Ferrara
- Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, UT, United States
| | - Princess Bombyck
- Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, UT, United States
| | - Zachary J. Fennel
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
| | - Lisha van Onselen
- Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, UT, United States
| | - Sohom Mookerjee
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, United States
| | - Katsuhiko Funai
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, United States
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
| | - J. David Symons
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, United States
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
| | - Micah J. Drummond
- Department of Physical Therapy and Athletic Training, University of Utah, Salt Lake City, UT, United States
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, United States
- Molecular Medicine Program, University of Utah, Salt Lake City, UT, United States
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9
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Barcena ML, Tonini G, Haritonow N, Breiter P, Milting H, Baczko I, Müller‐Werdan U, Ladilov Y, Regitz‐Zagrosek V. Sex and age differences in AMPK phosphorylation, mitochondrial homeostasis, and inflammation in hearts from inflammatory cardiomyopathy patients. Aging Cell 2023; 22:e13894. [PMID: 37365150 PMCID: PMC10410062 DOI: 10.1111/acel.13894] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 04/28/2023] [Accepted: 05/10/2023] [Indexed: 06/28/2023] Open
Abstract
Linked to exacerbated inflammation, myocarditis is a cardiovascular disease, which may lead to dilated cardiomyopathy. Although sex and age differences in the development of chronic myocarditis have been postulated, underlying cellular mechanisms remain poorly understood. In the current study, we aimed to investigate sex and age differences in mitochondrial homeostasis, inflammation, and cellular senescence. Cardiac tissue samples from younger and older patients with inflammatory dilated cardiomyopathy (DCMI) were used. The expression of Sirt1, phosphorylated AMPK, PGC-1α, Sirt3, acetylated SOD2, catalase, and several mitochondrial genes was analyzed to assess mitochondrial homeostasis. The expression of NF-κB, TLR4, and interleukins was used to examine the inflammatory state in the heart. Finally, several senescence markers and telomere length were investigated. Cardiac AMPK expression and phosphorylation were significantly elevated in male DCMI patients, whereas Sirt1 expression remained unchanged in all groups investigated. AMPK upregulation was accompanied by a preserved expression of all mitochondrial proteins/genes investigated in older male DCMI patients, whereas the expression of TOM40, TIM23, and the mitochondrial oxidative phosphorylation genes was significantly reduced in older female patients. Mitochondrial homeostasis in older male patients was further supported by the reduced acetylation of mitochondrial proteins as indicated by acetylated SOD2. The inflammatory markers NF-κB and TLR4 were downregulated in older male DCMI patients, whereas the expression of IL-18 was increased in older female patients. This was accompanied by progressed senescence in older DCMI hearts. In conclusion, older women experience more dramatic immunometabolic disorders on the cellular level than older men.
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Affiliation(s)
- Maria Luisa Barcena
- Department of Geriatrics and Medical GerontologyCharité –Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt‐Universität zu Berlin and Berlin Institute of HealthBerlinGermany
- DZHK (German Centre for Cardiovascular Research)BerlinGermany
| | - Greta Tonini
- Department of Geriatrics and Medical GerontologyCharité –Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt‐Universität zu Berlin and Berlin Institute of HealthBerlinGermany
| | - Natalie Haritonow
- Department of Geriatrics and Medical GerontologyCharité –Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt‐Universität zu Berlin and Berlin Institute of HealthBerlinGermany
| | - Pavelas Breiter
- Department of Geriatrics and Medical GerontologyCharité –Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt‐Universität zu Berlin and Berlin Institute of HealthBerlinGermany
- DZHK (German Centre for Cardiovascular Research)BerlinGermany
| | - Hendrik Milting
- Erich and Hanna Klessmann InstituteHeart and Diabetes Centre NRW, University Hospital of the Ruhr‐University BochumBad OeynhausenGermany
| | - Istvan Baczko
- Department of Pharmacology and Pharmacotherapy, Albert Szent‐Györgyi Medical SchoolUniversity of SzegedSzegedHungary
| | - Ursula Müller‐Werdan
- Department of Geriatrics and Medical GerontologyCharité –Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt‐Universität zu Berlin and Berlin Institute of HealthBerlinGermany
| | - Yury Ladilov
- Department of Geriatrics and Medical GerontologyCharité –Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt‐Universität zu Berlin and Berlin Institute of HealthBerlinGermany
- Department of Cardiovascular Surgery, Heart Center BrandenburgBrandenburg Medical SchoolBernau bei BerlinGermany
| | - Vera Regitz‐Zagrosek
- DZHK (German Centre for Cardiovascular Research)BerlinGermany
- Institute for Gender in Medicine, Center for Cardiovascular Research, Charité University HospitalBerlinGermany
- Department of CardiologyUniversity Hospital Zürich, University of ZürichZürichSwitzerland
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10
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Ghahari N, Telittchenko R, Loucif H, Isnard S, Routy JP, Olagnier D, van Grevenynghe J. Harnessing Autophagy to Overcome Antigen-Specific T-Cell Dysfunction: Implication for People Living with HIV-1. Int J Mol Sci 2023; 24:11018. [PMID: 37446195 DOI: 10.3390/ijms241311018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 06/29/2023] [Accepted: 07/01/2023] [Indexed: 07/15/2023] Open
Abstract
Like other chronic viral infections, HIV-1 persistence inhibits the development of antigen-specific memory T-cells, resulting in the exhaustion of the immune response and chronic inflammation. Autophagy is a major lysosome-dependent mechanism of intracellular large-target degradation such as lipid and protein aggregates, damaged organelles, and intracellular pathogens. Although it is known that autophagy may target HIV-1 for elimination, knowledge of its function as a metabolic contributor in such viral infection is only in its infancy. Recent data show that elite controllers (EC), who are HIV-1-infected subjects with natural and long-term antigen (Ag)-specific T-cell protection against the virus, are characterized by distinct metabolic autophagy-dependent features in their T-cells compared to other people living with HIV-1 (PLWH). Despite durable viral control with antiretroviral therapy (ART), HIV-1-specific immune dysfunction does not normalize in non-controller PLWH. Therefore, the hypothesis of inducing autophagy to strengthen their Ag-specific T-cell immunity against HIV-1 starts to be an enticing concept. The aim of this review is to critically analyze promises and potential limitations of pharmacological and dietary interventions to activate autophagy in an attempt to rescue Ag-specific T-cell protection among PLWH.
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Affiliation(s)
- Nazanin Ghahari
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, 531 Boulevard des Prairies, Laval, QC H7V 1M7, Canada
| | - Roman Telittchenko
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, 531 Boulevard des Prairies, Laval, QC H7V 1M7, Canada
| | - Hamza Loucif
- EVAH Corp., 500 Boulevard Cartier Ouest, Laval, QC H7V 5B7, Canada
| | - Stephane Isnard
- Chronic Viral Illness Service and Division of Hematology, McGill University Health Centre, Glen Site, Montreal, QC H4A 3J1, Canada
| | - Jean-Pierre Routy
- Chronic Viral Illness Service and Division of Hematology, McGill University Health Centre, Glen Site, Montreal, QC H4A 3J1, Canada
| | - David Olagnier
- Department of Biomedicine, Research Center for Innate Immunology, Aarhus University, 8000 Aarhus, Denmark
| | - Julien van Grevenynghe
- Institut National de la Recherche Scientifique (INRS), Centre Armand-Frappier Santé Biotechnologie, 531 Boulevard des Prairies, Laval, QC H7V 1M7, Canada
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11
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Guo Y, Guan T, Shafiq K, Yu Q, Jiao X, Na D, Li M, Zhang G, Kong J. Mitochondrial dysfunction in aging. Ageing Res Rev 2023; 88:101955. [PMID: 37196864 DOI: 10.1016/j.arr.2023.101955] [Citation(s) in RCA: 18] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 04/27/2023] [Accepted: 05/14/2023] [Indexed: 05/19/2023]
Abstract
Aging is a complex process that features a functional decline in many organelles. Although mitochondrial dysfunction is suggested as one of the determining factors of aging, the role of mitochondrial quality control (MQC) in aging is still poorly understood. A growing body of evidence points out that reactive oxygen species (ROS) stimulates mitochondrial dynamic changes and accelerates the accumulation of oxidized by-products through mitochondrial proteases and mitochondrial unfolded protein response (UPRmt). Mitochondrial-derived vesicles (MDVs) are the frontline of MQC to dispose of oxidized derivatives. Besides, mitophagy helps remove partially damaged mitochondria to ensure that mitochondria are healthy and functional. Although abundant interventions on MQC have been explored, over-activation or inhibition of any type of MQC may even accelerate abnormal energy metabolism and mitochondrial dysfunction-induced senescence. This review summarizes mechanisms essential for maintaining mitochondrial homeostasis and emphasizes that imbalanced MQC may accelerate cellular senescence and aging. Thus, appropriate interventions on MQC may delay the aging process and extend lifespan.
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Affiliation(s)
- Ying Guo
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Manitoba, Canada; Department of Forensic Medicine, Hebei North University, Zhangjiakou, China
| | - Teng Guan
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Kashfia Shafiq
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada
| | - Qiang Yu
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Xin Jiao
- Department of Forensic Medicine, Hebei North University, Zhangjiakou, China
| | - Donghui Na
- Department of Forensic Medicine, Hebei North University, Zhangjiakou, China
| | - Meiyu Li
- Department of Forensic Medicine, Hebei North University, Zhangjiakou, China
| | - Guohui Zhang
- Department of Forensic Medicine, Hebei North University, Zhangjiakou, China.
| | - Jiming Kong
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Manitoba, Canada.
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12
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Picca A, Lozanoska-Ochser B, Calvani R, Coelho-Júnior HJ, Leewenburgh C, Marzetti E. Inflammatory, mitochondrial, and senescence-related markers: Underlying biological pathways of muscle aging and new therapeutic targets. Exp Gerontol 2023; 178:112204. [PMID: 37169101 DOI: 10.1016/j.exger.2023.112204] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2023] [Revised: 05/04/2023] [Accepted: 05/09/2023] [Indexed: 05/13/2023]
Abstract
The maintenance of functional health is pivotal for achieving independent life in older age. The aged muscle is characterized by ultrastructural changes, including loss of type I and type II myofibers and a greater proportion of cytochrome c oxidase deficient and succinate dehydrogenase positive fibers. Both intrinsic (e.g., altered proteostasis, DNA damage, and mitochondrial dysfunction) and extrinsic factors (e.g., denervation, altered metabolic regulation, declines in satellite cells, and inflammation) contribute to muscle aging. Being a hub for several cellular activities, mitochondria are key to myocyte viability and mitochondrial dysfunction has been implicated in age-associated physical decline. The maintenance of functional organelles via mitochondrial quality control (MQC) processes is, therefore, crucial to skeletal myofiber viability and organismal health. The autophagy-lysosome pathway has emerged as a critical step of MQC in muscle by disposing organelles and proteins via their tagging for autophagosome incorporation and delivery to the lysosome for clearance. This pathway was found to be altered in muscle of physically inactive older adults. A relationship between this pathway and muscle tissue composition of the lower extremities as well as physical performance was also identified. Therefore, integrating muscle structure and myocyte quality control measures in the evaluation of muscle health may be a promising strategy for devising interventions fostering muscle health.
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Affiliation(s)
- Anna Picca
- Department of Medicine and Surgery, LUM University, Casamassima, 70100 Bari, Italy; Fondazione Policlinico Universitario "Agostino Gemelli" IRCSS, 00168 Rome, Italy
| | - Biliana Lozanoska-Ochser
- Department of Medicine and Surgery, LUM University, Casamassima, 70100 Bari, Italy; DAHFMO Unit of Histology and Medical Embryology, Sapienza University of Rome, 00161 Rome, Italy
| | - Riccardo Calvani
- Fondazione Policlinico Universitario "Agostino Gemelli" IRCSS, 00168 Rome, Italy; Department of Geriatrics and Orthopedics, Università Cattolica del Sacro Cuore, 00168 Rome, Italy.
| | - Hélio José Coelho-Júnior
- Department of Geriatrics and Orthopedics, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | | | - Emanuele Marzetti
- Fondazione Policlinico Universitario "Agostino Gemelli" IRCSS, 00168 Rome, Italy; Department of Geriatrics and Orthopedics, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
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13
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Su P, Chen JG, Tang DH. Exercise against nonalcoholic fatty liver disease: Possible role and mechanism of lipophagy. Life Sci 2023; 327:121837. [PMID: 37301321 DOI: 10.1016/j.lfs.2023.121837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 05/25/2023] [Accepted: 06/05/2023] [Indexed: 06/12/2023]
Abstract
Nonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease worldwide. NAFLD is prevalent in about 30% of people worldwide. The lack of physical activity is considered as one of the risks for NAFLD, and approximately one-third of NAFLD patients hardly engage in physical activity. It is acknowledged that exercise is one of the optimal non-pharmacological methods for preventing and treating NAFLD. Different forms of exercise such as aerobic exercise, resistance exercise and even simply physical activity in a higher level can be beneficial in reducing liver lipid accumulation and disease progression for NAFLD patients. In NAFLD patients, exercise is helpful in lowering steatosis and enhancing liver function. The mechanisms underlying the prevention and treatment of NAFLD by exercise are various and complex. Current studies on the mechanisms have focused on the pro-lipolytic, anti-inflammatory, and antioxidant and lipophagy. Promotion of lipophagy is regarded as an important mechanism for prevention and improvement of NAFLD by exercise. Recent studies have investigated the above mechanism, yet the potential mechanism has not been completely elucidated. Thus, in this review, we cover the recent advances of exercise-promoted lipophagy in NAFLD treatment and prevention. Furthermore, given the fact that exercise activates SIRT1, we discuss the possible regulatory mechanisms of lipophagy by SIRT1 during exercise. These mechanisms need to be verified by further experimental studies.
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Affiliation(s)
- Pei Su
- Department of College of P.E. and Sport, Beijing Normal University, No. 19, Xinjiekouwai St, Haidian District, Beijing 100875, People's Republic of China.
| | - Jian-Gang Chen
- Department of College of P.E. and Sport, Beijing Normal University, No. 19, Xinjiekouwai St, Haidian District, Beijing 100875, People's Republic of China.
| | - Dong-Hui Tang
- Department of College of P.E. and Sport, Beijing Normal University, No. 19, Xinjiekouwai St, Haidian District, Beijing 100875, People's Republic of China.
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14
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Coradduzza D, Congiargiu A, Chen Z, Cruciani S, Zinellu A, Carru C, Medici S. Humanin and Its Pathophysiological Roles in Aging: A Systematic Review. BIOLOGY 2023; 12:biology12040558. [PMID: 37106758 PMCID: PMC10135985 DOI: 10.3390/biology12040558] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2023] [Revised: 04/03/2023] [Accepted: 04/03/2023] [Indexed: 04/29/2023]
Abstract
BACKGROUND Senescence is a cellular aging process in all multicellular organisms. It is characterized by a decline in cellular functions and proliferation, resulting in increased cellular damage and death. These conditions play an essential role in aging and significantly contribute to the development of age-related complications. Humanin is a mitochondrial-derived peptide (MDP), encoded by mitochondrial DNA, playing a cytoprotective role to preserve mitochondrial function and cell viability under stressful and senescence conditions. For these reasons, humanin can be exploited in strategies aiming to counteract several processes involved in aging, including cardiovascular disease, neurodegeneration, and cancer. Relevance of these conditions to aging and disease: Senescence appears to be involved in the decay in organ and tissue function, it has also been related to the development of age-related diseases, such as cardiovascular conditions, cancer, and diabetes. In particular, senescent cells produce inflammatory cytokines and other pro-inflammatory molecules that can participate to the development of such diseases. Humanin, on the other hand, seems to contrast the development of such conditions, and it is also known to play a role in these diseases by promoting the death of damaged or malfunctioning cells and contributing to the inflammation often associated with them. Both senescence and humanin-related mechanisms are complex processes that have not been fully clarified yet. Further research is needed to thoroughly understand the role of such processes in aging and disease and identify potential interventions to target them in order to prevent or treat age-related conditions. OBJECTIVES This systematic review aims to assess the potential mechanisms underlying the link connecting senescence, humanin, aging, and disease.
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Affiliation(s)
| | | | - Zhichao Chen
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy
| | - Sara Cruciani
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy
| | - Angelo Zinellu
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy
| | - Ciriaco Carru
- Department of Biomedical Sciences, University of Sassari, 07100 Sassari, Italy
- Control Quality Unit, Azienda-Ospedaliera Universitaria (AOU), 07100 Sassari, Italy
| | - Serenella Medici
- Department of Chemical, Physical, Mathematical and Natural Sciences, University of Sassari, 07100 Sassari, Italy
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15
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Paez HG, Pitzer CR, Alway SE. Age-Related Dysfunction in Proteostasis and Cellular Quality Control in the Development of Sarcopenia. Cells 2023; 12:cells12020249. [PMID: 36672183 PMCID: PMC9856405 DOI: 10.3390/cells12020249] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2022] [Revised: 01/04/2023] [Accepted: 01/04/2023] [Indexed: 01/11/2023] Open
Abstract
Sarcopenia is a debilitating skeletal muscle disease that accelerates in the last decades of life and is characterized by marked deficits in muscle strength, mass, quality, and metabolic health. The multifactorial causes of sarcopenia have proven difficult to treat and involve a complex interplay between environmental factors and intrinsic age-associated changes. It is generally accepted that sarcopenia results in a progressive loss of skeletal muscle function that exceeds the loss of mass, indicating that while loss of muscle mass is important, loss of muscle quality is the primary defect with advanced age. Furthermore, preclinical models have suggested that aged skeletal muscle exhibits defects in cellular quality control such as the degradation of damaged mitochondria. Recent evidence suggests that a dysregulation of proteostasis, an important regulator of cellular quality control, is a significant contributor to the aging-associated declines in muscle quality, function, and mass. Although skeletal muscle mammalian target of rapamycin complex 1 (mTORC1) plays a critical role in cellular control, including skeletal muscle hypertrophy, paradoxically, sustained activation of mTORC1 recapitulates several characteristics of sarcopenia. Pharmaceutical inhibition of mTORC1 as well as caloric restriction significantly improves muscle quality in aged animals, however, the mechanisms controlling cellular proteostasis are not fully known. This information is important for developing effective therapeutic strategies that mitigate or prevent sarcopenia and associated disability. This review identifies recent and historical understanding of the molecular mechanisms of proteostasis driving age-associated muscle loss and suggests potential therapeutic interventions to slow or prevent sarcopenia.
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Affiliation(s)
- Hector G. Paez
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Integrated Biomedical Sciences Graduate Program, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Laboratory of Muscle Biology and Sarcopenia, Department of Physical Therapy, College of Health Professions, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Center for Muscle, Metabolism and Neuropathology, Division of Regenerative and Rehabilitation Sciences, College of Health Professions, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Christopher R. Pitzer
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Integrated Biomedical Sciences Graduate Program, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Laboratory of Muscle Biology and Sarcopenia, Department of Physical Therapy, College of Health Professions, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Center for Muscle, Metabolism and Neuropathology, Division of Regenerative and Rehabilitation Sciences, College of Health Professions, University of Tennessee Health Science Center, Memphis, TN 38163, USA
| | - Stephen E. Alway
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Integrated Biomedical Sciences Graduate Program, College of Graduate Health Sciences, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Laboratory of Muscle Biology and Sarcopenia, Department of Physical Therapy, College of Health Professions, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- Center for Muscle, Metabolism and Neuropathology, Division of Regenerative and Rehabilitation Sciences, College of Health Professions, University of Tennessee Health Science Center, Memphis, TN 38163, USA
- The Tennessee Institute of Regenerative Medicine, Memphis, TN 38163, USA
- Correspondence:
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16
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Picca A, Triolo M, Wohlgemuth SE, Martenson MS, Mankowski RT, Anton SD, Marzetti E, Leeuwenburgh C, Hood DA. Relationship between Mitochondrial Quality Control Markers, Lower Extremity Tissue Composition, and Physical Performance in Physically Inactive Older Adults. Cells 2023; 12:183. [PMID: 36611976 PMCID: PMC9818256 DOI: 10.3390/cells12010183] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/29/2022] [Accepted: 12/30/2022] [Indexed: 01/03/2023] Open
Abstract
Altered mitochondrial quality and function in muscle may be involved in age-related physical function decline. The role played by the autophagy-lysosome system, a major component of mitochondrial quality control (MQC), is incompletely understood. This study was undertaken to obtain initial indications on the relationship between autophagy, mitophagy, and lysosomal markers in muscle and measures of physical performance and lower extremity tissue composition in young and older adults. Twenty-three participants were enrolled, nine young (mean age: 24.3 ± 4.3 years) and 14 older adults (mean age: 77.9 ± 6.3 years). Lower extremity tissue composition was quantified volumetrically by magnetic resonance imaging and a tissue composition index was calculated as the ratio between muscle and intermuscular adipose tissue volume. Physical performance in older participants was assessed via the Short Physical Performance Battery (SPPB). Protein levels of the autophagy marker p62, the mitophagy mediator BCL2/adenovirus E1B 19 kDa protein-interacting protein 3 (BNIP3), the lysosomal markers transcription factor EB, vacuolar-type ATPase, and lysosomal-associated membrane protein 1 were measured by Western immunoblotting in vastus lateralis muscle biopsies. Older adults had smaller muscle volume and lower tissue composition index than young participants. The protein content of p62 and BNIP3 was higher in older adults. A negative correlation was detected between p62 and BNIP3 and the tissue composition index. p62 and BNIP3 were also related to the performance on the 5-time sit-to-stand test of the SPPB. Our results suggest that an altered expression of markers of the autophagy/mitophagy-lysosomal system is related to deterioration of lower extremity tissue composition and muscle dysfunction. Additional studies are needed to clarify the role of defective MQC in human muscle aging and identify novel biological targets for drug development.
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Affiliation(s)
- Anna Picca
- Fondazione Policlinico Universitario “A. Gemelli”, IRCCS, 00168 Rome, Italy
- Department of Medicine and Surgery, LUM University, 70100 Casamassima, Italy
| | - Matthew Triolo
- Muscle Health Research Centre, York University, Toronto, ON M3J 1P3, Canada
- School of Kinesiology and Health Science, York University, Toronto, ON M3J 1P3, Canada
| | | | - Matthew S. Martenson
- Department of Physiology and Aging, University of Florida, Gainesville, FL 32610, USA
| | - Robert T. Mankowski
- Department of Physiology and Aging, University of Florida, Gainesville, FL 32610, USA
| | - Stephen D. Anton
- Department of Physiology and Aging, University of Florida, Gainesville, FL 32610, USA
| | - Emanuele Marzetti
- Fondazione Policlinico Universitario “A. Gemelli”, IRCCS, 00168 Rome, Italy
- Department of Geriatrics and Orthopedics, Università Cattolica del Sacro Cuore, 00168 Rome, Italy
| | | | - David A. Hood
- Muscle Health Research Centre, York University, Toronto, ON M3J 1P3, Canada
- School of Kinesiology and Health Science, York University, Toronto, ON M3J 1P3, Canada
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17
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Tian X, Lou S, Shi R. From mitochondria to sarcopenia: role of 17β-estradiol and testosterone. Front Endocrinol (Lausanne) 2023; 14:1156583. [PMID: 37152937 PMCID: PMC10157222 DOI: 10.3389/fendo.2023.1156583] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/03/2023] [Indexed: 05/09/2023] Open
Abstract
Sarcopenia, characterized by a loss of muscle mass and strength with aging, is prevalent in older adults. Although the exact mechanisms underlying sarcopenia are not fully understood, evidence suggests that the loss of mitochondrial integrity in skeletal myocytes has emerged as a pivotal contributor to the complex etiology of sarcopenia. Mitochondria are the primary source of ATP production and are also involved in generating reactive oxygen species (ROS), regulating ion signals, and initiating apoptosis signals in muscle cells. The accumulation of damaged mitochondria due to age-related impairments in any of the mitochondrial quality control (MQC) processes, such as proteostasis, biogenesis, dynamics, and mitophagy, can contribute to the decline in muscle mass and strength associated with aging. Interestingly, a decrease in sex hormones (e.g., 17β-estradiol and testosterone), which occurs with aging, has also been linked to sarcopenia. Indeed, 17β-estradiol and testosterone targeted mitochondria and exhibited activities in regulating mitochondrial functions. Here, we overview the current literature on the key mechanisms by which mitochondrial dysfunction contribute to the development and progression of sarcopenia and the potential modulatory effects of 17β-estradiol and testosterone on mitochondrial function in this context. The advance in its understanding will facilitate the development of potential therapeutic agents to mitigate and manage sarcopenia.
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18
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Triolo M, Bhattacharya D, Hood DA. Denervation induces mitochondrial decline and exacerbates lysosome dysfunction in middle-aged mice. Aging (Albany NY) 2022; 14:8900-8913. [PMID: 36342767 PMCID: PMC9740366 DOI: 10.18632/aging.204365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Accepted: 10/24/2022] [Indexed: 11/06/2022]
Abstract
With age, skeletal muscle undergoes a progressive decline in size and quality. Imbalanced mitochondrial turnover and the resultant dysfunction contribute to these phenotypic alterations. Motor neuron denervation (Den) is a contributor to the etiology of muscle atrophy associated with age. Further, aged muscle exhibits reduced plasticity to both enhanced and suppressed contractile activity. It remains unclear when the onset of this blunted response occurs, and how middle-aged muscle adapts to denervation. The purpose of this study was to compare mitochondrial turnover pathways in young (Y, ~5months) and middle-aged (MA, ~15months) mice, and determine the influence of Den. Transgenic mt-Keima mice were subjected to 1,3 or 7 days of Den. Muscle mass, mitochondrial content, and PGC-1α protein were not different between Y and MA mice. However, indications of enhanced mitochondrial fission and mitophagy were evident in MA muscle which were supported by a greater abundance of lysosome proteins. Den resulted in muscle atrophy and reductions in mitochondrial protein content by 7-days. These changes occurred concomitant with modest decreases in PGC-1α protein, but without further elevations in mitophagy. Although both autophagosomal and lysosomal proteins were elevated, evidence of lysosome dysfunction was present following Den in MA mice. These data suggest that increases in fission drive an acceleration of mitophagy in muscle of MA mice to preserve mitochondrial quality. Den exacerbates the aging phenotype by reducing biogenesis in the absence of a change in mitophagy, perhaps limited by lysosomal capacity, leading to an accumulation of dysfunctional mitochondria with an age-related loss of neuromuscular innervation.
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Affiliation(s)
- Matthew Triolo
- Muscle Health Research Centre, York University, Toronto, Ontario M3J 1P3, Canada,School of Kinesiology and Health Science, York University, Toronto, Ontario M3J 1P3, Canada
| | - Debasmita Bhattacharya
- Muscle Health Research Centre, York University, Toronto, Ontario M3J 1P3, Canada,School of Kinesiology and Health Science, York University, Toronto, Ontario M3J 1P3, Canada
| | - David A. Hood
- Muscle Health Research Centre, York University, Toronto, Ontario M3J 1P3, Canada,School of Kinesiology and Health Science, York University, Toronto, Ontario M3J 1P3, Canada
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19
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Morales-Scholz MG, Wette SG, Stokie JR, Tepper BT, Swinton C, Hamilton DL, Dwyer KM, Murphy RM, Howlett KF, Shaw CS. Muscle fiber type-specific autophagy responses following an overnight fast and mixed meal ingestion in human skeletal muscle. Am J Physiol Endocrinol Metab 2022; 323:E242-E253. [PMID: 35793481 DOI: 10.1152/ajpendo.00015.2022] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The aim of the present study was to investigate the fiber type-specific abundance of autophagy-related proteins after an overnight fast and following ingestion of a mixed meal in human skeletal muscle. Twelve overweight, healthy young male volunteers underwent a 3-h mixed meal tolerance test following an overnight fast. Blood samples were collected in the overnight-fasted state and throughout the 180-min postmeal period. Skeletal muscle biopsies were collected in the fasted state, and at 30 and 90 min after meal ingestion. Protein content of key autophagy markers and upstream signaling responses were measured in whole muscle and pooled single fibers using immunoblotting. In the fasted state, type I fibers displayed lower LC3B-I but higher LC3B-II abundance and higher LC3B-II/LC3B-I ratio compared with type II fibers (P < 0.05). However, there were no fiber type differences in p62/SQSTM1, unc-51 like autophagy activating kinase (ULK1), ATG5, or ATG12 (P > 0.05). Compared with the fasted state, there was a reduction in LC3B-II abundance, indicative of lower autophagosome content, in whole muscle and in both type I and type II fibers following meal ingestion (P < 0.05). This reduction in autophagosome content occurred alongside similar increases in p-AktS473 and p-mTORS2448 in both type I and type II muscle fibers (P < 0.05). In human skeletal muscle, type I fibers have a greater autophagosome content than type II fibers in the overnight-fasted state despite comparable abundance of other key upstream autophagy proteins. Autophagy is rapidly inhibited in both fiber types following the ingestion of a mixed meal.NEW & NOTEWORTHY This study examined the fiber type-specific content of key autophagy proteins in human muscle. We showed that markers of autophagosome content are higher in type I fibers in the overnight-fasted state, whereas autophagy is rapidly inhibited in both type I and type II fibers after the ingestion of a mixed meal.
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Affiliation(s)
- María G Morales-Scholz
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
- Human Movement Sciences Research Center (CIMOHU), University of Costa Rica, San José, Costa Rica
| | - Stefan G Wette
- Department of Biochemistry and Chemistry, School of Agriculture, Biomedicine and Environment (SABE), La Trobe University, Melbourne, Australia
| | - Jayden R Stokie
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Bianca T Tepper
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Courtney Swinton
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - David L Hamilton
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Karen M Dwyer
- School of Medicine, Deakin University, Geelong, Australia
| | - Robyn M Murphy
- Department of Biochemistry and Chemistry, School of Agriculture, Biomedicine and Environment (SABE), La Trobe University, Melbourne, Australia
| | - Kirsten F Howlett
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
| | - Christopher S Shaw
- Institute for Physical Activity and Nutrition, School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia
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