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Amos MG, Rosa-Caldwell ME, Haynie WS, Dunlap KR, Lim S, Jansen LT, Brown JL, Lee DE, Washington TA, Wiggs MP, Greene NP. OXIDATIVE METABOLISM DURING THE TIME-COURSE OF DISUSE ATROPHY IN MALE AND FEMALE MICE. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000670176.31047.b8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Rosa-Caldwell ME, Lim S, Haynie WS, Jansen LT, Dunlap KR, Washington TA, Greene NP. Increasing Mitochondrial Content Does Not Protect Against Disuse-induced Muscle Atrophy. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000670152.64055.9f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Westervelt LC, Lim S, Rosa-Caldwell ME, Haynie WS, Dunlap KR, Jansen LT, Wiggs MP, Washington TA, Greene NP. Mitochondrial Health During The Development Of Cancer Cachexia In Female Mice. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000685424.67307.3f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Haynie WS, Rankin KL, Rosa-Caldwell ME, Bejarano KA, Lim S, Greene NP, Washington TA. Leucine Supplementation Exacerbates Atrophy In Cancer Cachectic Mice. Med Sci Sports Exerc 2020. [DOI: 10.1249/01.mss.0000685416.28401.83] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Rosa-Caldwell ME, Jansen LT, Lim S, Dunlap KR, Haynie WS, Washington TA, Greene NP. Neither autophagy nor exercise training mode affect exercise-induced beneficial adaptations in high fat-fed mice. SPORTS MEDICINE AND HEALTH SCIENCE 2020; 2:44-53. [PMID: 35783331 PMCID: PMC9219353 DOI: 10.1016/j.smhs.2020.03.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 02/28/2020] [Accepted: 03/04/2020] [Indexed: 01/06/2023] Open
Abstract
Purpose Methods Results Conclusions
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Rosa-Caldwell ME, Fix DK, Washington TA, Greene NP. Muscle alterations in the development and progression of cancer-induced muscle atrophy: a review. J Appl Physiol (1985) 2019; 128:25-41. [PMID: 31725360 DOI: 10.1152/japplphysiol.00622.2019] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Cancer cachexia-cancer-associated body weight and muscle loss-is a significant predictor of mortality and morbidity in cancer patients across a variety of cancer types. However, despite the negative prognosis associated with cachexia onset, there are no clinical therapies approved to treat or prevent cachexia. This lack of treatment may be partially due to the relative dearth of literature on mechanisms occurring within the muscle before the onset of muscle wasting. Therefore, the purpose of this review is to compile the current scientific literature on mechanisms contributing to the development and progression of cancer cachexia, including protein turnover, inflammatory signaling, and mitochondrial dysfunction. We define "development" as changes in cell function occurring before the onset of cachexia and "progression" as alterations to cell function that coincide with the exacerbation of muscle wasting. Overall, the current literature suggests that multiple aspects of cellular function, such as protein turnover, inflammatory signaling, and mitochondrial quality, are altered before the onset of muscle loss during cancer cachexia and clearly highlights the need to study more thoroughly the developmental stages of cachexia. The studying of these early aberrations will allow for the development of effective therapeutics to prevent the onset of cachexia and improve health outcomes in cancer patients.
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Rosa-Caldwell ME, Brown JL, Lee DE, Wiggs MP, Perry RA, Haynie WS, Caldwell AR, Washington TA, Lo WJ, Greene NP. Hepatic alterations during the development and progression of cancer cachexia. Appl Physiol Nutr Metab 2019; 45:500-512. [PMID: 31618604 DOI: 10.1139/apnm-2019-0407] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cancer-associated bodyweight loss (cachexia) is a hallmark of many cancers and is associated with decreased quality of life and increased mortality. Hepatic function can dramatically influence whole-body energy expenditure and may therefore significantly influence whole-body health during cancer progression. The purpose of this study was to examine alterations in markers of hepatic metabolism and physiology during cachexia progression. Male C57BL/6J mice were injected with 1 × 106 Lewis Lung Carcinoma cells dissolved in 100 μL PBS and cancer was allowed to develop for 1, 2, 3, or 4 weeks. Control animals were injected with an equal volume of phosphate-buffered saline. Livers were analyzed for measures of metabolism, collagen deposition, protein turnover, and mitochondrial quality. Animals at 4 weeks had ∼30% larger livers compared with all other groups. Cancer progression was associated with altered regulators of fat metabolism. Additionally, longer duration of cancer development was associated with ∼3-fold increased regulators of collagen deposition as well as phenotypic collagen content, suggesting increased liver fibrosis. Mitochondrial quality control regulators appeared to be altered before any phenotypic alterations to collagen deposition. While induction of Akt was noted, downstream markers of protein synthesis were not altered. In conclusions, cancer cachexia progression is associated with hepatic pathologies, specifically liver fibrosis. Alterations to mitochondrial quality control mechanisms appear to precede this fibrotic phenotype, potentially suggesting mitochondrial mechanisms for the development of hepatic pathologies during the development and progression of cancer cachexia. Novelty Cachexia progression results in liver collagen deposition and fibrosis. Alterations in mitochondrial quality control may precede liver pathologies during cachexia.
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Rosa-Caldwell ME, Brown JL, Perry RA, Shimkus KL, Shirazi-Fard Y, Brown LA, Hogan HA, Fluckey JD, Washington TA, Wiggs MP, Greene NP. Regulation of mitochondrial quality following repeated bouts of hindlimb unloading. Appl Physiol Nutr Metab 2019; 45:264-274. [PMID: 31340136 DOI: 10.1139/apnm-2019-0218] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Muscle disuse impairs muscle quality and is associated with increased mortality. Little is known regarding additive effects of multiple bouts of disuse, which is a common occurrence in patients experiencing multiple surgeries. Mitochondrial quality is vital to muscle health and quality; however, to date mitochondrial quality control has not been investigated following multiple bouts of disuse. Therefore, the purpose of this study was to investigate mitochondrial quality controllers during multiple bouts of disuse by hindlimb unloading. Male rats (n ∼ 8/group) were assigned to the following groups: hindlimb unloading for 28 days, hindlimb unloading with 56 days of reloading, 2 bouts of hindlimb unloading separated by a recovery phase of 56 days of reloading, 2 bouts of hindlimb unloading and recovery after each disuse, or control animals with no unloading. At designated time points, tissues were collected for messenger RNA and protein analysis of mitochondrial quality. Measures of mitochondrial biogenesis, such as proliferator-activated receptor gamma coactivator 1 alpha, decreased 30%-40% with unloading with no differences noted between unloading conditions. Measures of mitochondrial translation were 40%-50% lower in unloading conditions, with no differences noted between bouts of unloading. Measures of mitophagy were 40%-50% lower with reloading, with no differences noted between reloading conditions. In conclusion, disuse causes alterations in measures of mitochondrial quality; however, multiple bouts of disuse does not appear to have additive effects. Novelty Disuse atrophy causes multiple alterations to mitochondrial quality control. With sufficient recovery most detriments to mitochondrial quality control are fixed. In general, multiple bouts of disuse do not produce additive effects.
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Rosa-Caldwell ME, Jansen LT, Lim S, Dunlap KR, Haynie WA, Bejarano KA, Washington TA, Greene NP. Neither Autophagy Inhibition Nor High Intensity Interval Training Alter Exercise Adaptations During High Fat Feeding. Med Sci Sports Exerc 2019. [DOI: 10.1249/01.mss.0000561650.31646.ab] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Lim S, Lee DE, Rosa-Caldwell ME, Brown JL, Washington TA, Greene NP. Inhibition Of miR-16 In Vitro Decreases Glucose Uptake And Insulin Signaling. Med Sci Sports Exerc 2019. [DOI: 10.1249/01.mss.0000563420.53470.59] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Bejarano KA, Haynie WS, Perry RA, Brown LA, Lee DE, Brown JL, Rosa-Caldwell ME, Greene NP, Washington TA. Preliminary study: Leucine Supplementation Exacerbates Muscle Wasting Independent of the Ubiquitin-Proteasome System. Med Sci Sports Exerc 2019. [DOI: 10.1249/01.mss.0000562009.45254.47] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Jansen LT, Rosa-Caldwell ME, Haynie WS, Lim S, Dunlap K, Brown JL, Lee DE, Perry RA, Wiggs MP, Washington TA, Greene NP. Sex Differences in Anabolic Regulators during Development of Atrophic Pathology in Hindlimb-Unloading-Induced Disuse. Med Sci Sports Exerc 2019. [DOI: 10.1249/01.mss.0000561790.58578.1f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Blackwell TA, Cervenka I, Khatri B, Brown JL, Rosa-Caldwell ME, Lee DE, Perry RA, Brown LA, Haynie WS, Wiggs MP, Bottje WG, Washington TA, Kong BC, Ruas JL, Greene NP. Transcriptomic analysis of the development of skeletal muscle atrophy in cancer-cachexia in tumor-bearing mice. Physiol Genomics 2018; 50:1071-1082. [PMID: 30289747 DOI: 10.1152/physiolgenomics.00061.2018] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Cancer-cachexia (CC) is a wasting condition directly responsible for 20-40% of cancer-related deaths. The mechanisms controlling development of CC-induced muscle wasting are not fully elucidated. Most investigations focus on the postcachectic state and do not examine progression of the condition. We recently demonstrated mitochondrial degenerations precede muscle wasting in time course progression of CC. However, the extent of muscle perturbations before wasting in CC is unknown. Therefore, we performed global gene expression analysis in CC-induced muscle wasting to enhance understanding of intramuscular perturbations across the development of CC. Lewis lung carcinoma (LLC) was injected into the hind-flank of C57BL6/J mice at 8 wk of age with tumor allowed to develop for 1, 2, 3, or 4 wk and compared with PBS-injected control. Muscle wasting was evident at 4 wk LLC. RNA sequencing of gastrocnemius muscle samples showed widespread alterations in LLC compared with PBS animals with largest differences seen in 4 wk LLC, suggesting extensive transcriptomic alterations concurrent to muscle wasting. Commonly altered pathways included: mitochondrial dysfunction and protein ubiquitination, along with other less studied processes in this condition regulating transcription/translation and cytoskeletal structure. Current findings present novel evidence of transcriptomic shifts and altered cellular pathways in CC-induced muscle wasting.
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Brown JL, Lee DE, Rosa-Caldwell ME, Brown LA, Perry RA, Haynie WS, Huseman K, Sataranatarajan K, Van Remmen H, Washington TA, Wiggs MP, Greene NP. Protein imbalance in the development of skeletal muscle wasting in tumour-bearing mice. J Cachexia Sarcopenia Muscle 2018; 9:987-1002. [PMID: 30328290 PMCID: PMC6204589 DOI: 10.1002/jcsm.12354] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2018] [Accepted: 08/28/2018] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Cancer cachexia occurs in approximately 80% of cancer patients and is a key contributor to cancer-related death. The mechanisms controlling development of tumour-induced muscle wasting are not fully elucidated. Specifically, the progression and development of cancer cachexia are underexplored. Therefore, we examined skeletal muscle protein turnover throughout the development of cancer cachexia in tumour-bearing mice. METHODS Lewis lung carcinoma (LLC) was injected into the hind flank of C57BL6/J mice at 8 weeks age with tumour allowed to develop for 1, 2, 3, or 4 weeks and compared with PBS injected control. Muscle size was measured by cross-sectional area analysis of haematoxylin and eosin stained tibialis anterior muscle. 2 H2 O was used to assess protein synthesis throughout the development of cancer cachexia. Immunoblot and RT-qPCR were used to measure regulators of protein turnover. TUNEL staining was utilized to measure apoptotic nuclei. LLC conditioned media (LCM) treatment of C2C12 myotubes was used to analyse cancer cachexia in vitro. RESULTS Muscle cross-sectional area decreased ~40% 4 weeks following tumour implantation. Myogenic signalling was suppressed in tumour-bearing mice as soon as 1 week following tumour implantation, including lower mRNA contents of Pax7, MyoD, CyclinD1, and Myogenin, when compared with control animals. AchRδ and AchRε mRNA contents were down-regulated by ~50% 3 weeks following tumour implantation. Mixed fractional synthesis rate protein synthesis was ~40% lower in 4 week tumour-bearing mice when compared with PBS controls. Protein ubiquitination was elevated by ~50% 4 weeks after tumour implantation. Moreover, there was an increase in autophagy machinery after 4 weeks of tumour growth. Finally, ERK and p38 MAPK phosphorylations were fourfold and threefold greater than control muscle 4 weeks following tumour implantation, respectively. Inhibition of p38 MAPK, but not ERK MAPK, in vitro partially rescued LCM-induced loss of myotube diameter. CONCLUSIONS Our findings work towards understanding the pathophysiological signalling in skeletal muscle in the initial development of cancer cachexia. Shortly following the onset of the tumour-bearing state alterations in myogenic regulatory factors are apparent, suggesting early onset alterations in the capacity for myogenic induction. Cancer cachexia presents with a combination of a loss of protein synthesis and increased markers of protein breakdown, specifically in the ubiquitin-proteasome system. Also, p38 MAPK may be a potential therapeutic target to combat cancer cachexia via a p38-FOX01-atrogene-ubiquitin-proteasome mechanism.
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Ramey S, Rosa-Caldwell ME, Brown JL, Perry RA, Haynie WA, Caldwell AR, Washington TA, Wiggs MP, Greene NP. Cancer Cachexia. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000535785.87585.83] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Haynie WS, Perry RA, Brown LA, Lee DE, Brown JL, Rose-Caldwell ME, Greene NP, Washington TA. Muscle Morphology is Not Altered in PGC-1α Transgenic Mice following Bupivacaine Injection. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000538654.53688.77] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Rosa-Caldwell ME, Brown JL, Lee DE, Washington TA, Greene NP. Tumor Derived Factors Induce Muscle Mitochondria Hyperpolarization And Subsequent Superoxide Production. Med Sci Sports Exerc 2018. [DOI: 10.1249/01.mss.0000535572.42104.0f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Lee DE, Brown JL, Rosa‐Caldwell ME, Perry RA, Haynie WA, Washington TA, Wiggs MP, Rajaram N, Greene NP. Cancer‐induced Metabolic Cardiotoxicity Characterized through Optical Metabolic Imaging. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.618.19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Rosa‐Caldwell M, Brown JL, Lee DE, Perry RA, Haynie WA, Caldwell AR, Washington TA, Wiggs MP, Greene NP. Alterations in Hepatic Protein Synthetic Signaling During the Progression of Cancer Cachexia. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.608.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Greene NP, Brown JL, Rosa‐Caldwell ME, Lee DE, Haynie WA, Perry RA, Washington TA, Wiggs MP. Early mitochondrial degeneration in the development of disuse‐induced muscle atrophy. FASEB J 2018. [DOI: 10.1096/fasebj.2018.32.1_supplement.856.9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Greene NP, Brown JL, Rosa-Caldwell ME, Lee DE, Blackwell TA, Washington TA. Skeletal Muscle Insulin Resistance as a Precursor to Diabetes: Beyond Glucoregulation. Curr Diabetes Rev 2018; 14:113-128. [PMID: 27875947 DOI: 10.2174/1573399813666161122123636] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/15/2016] [Revised: 11/10/2016] [Accepted: 11/14/2016] [Indexed: 11/22/2022]
Abstract
BACKGROUND Prevalence of Type 2 Diabetes Mellitus (T2DM) has reached pandemic levels in the Western societies. T2DM begins with the development of peripheral insulin resistance which prior research suggests may commonly originate within the skeletal muscle. A number of mechanisms have been proposed for the development of muscle insulin resistance including those of classical glucose handling, and also other cellular derangements observed in this disease which include mitochondrial degeneration, alterations in muscle protein turnover and early evidences for dysregulation of the microRNAs. The purpose of the current review is to examine the current findings on these latter aspects of mitochondrial maintenance, protein turnover and microRNA dysregulation along with the potential implications for these derangements in the development of insulin resistance and hence T2DM. We summarize multiple evidences for the degeneration of mitochondria and known elements of the processes regulating mitochondrial quality. Subsequently, we examine current findings of the alterations in muscle protein synthesis and autophagic protein degradation in T2DM and potential feedback of these systems onto canonical insulin signaling. Finally, evidences have emerged for the dysregulation of microRNAs in muscle insulin resistance. Of note early data point to several microRNAs altered by the insulin resistant state which exhibit relations to classic insulin signaling and the other processes discussed here. CONCLUSION Considering that T2DM may be initiated with muscle insulin resistance, improved understanding of the dysregulation of these metabolic parameters of skeletal muscle in the pathogenesis of T2DM may be key to developing efficacious therapeutic modalities to prevent and treat this condition.
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Brown JL, Rosa‐Caldwell ME, Lee DE, Blackwell TA, Brown LA, Perry RA, Haynie WS, Hardee JP, Carson JA, Wiggs MP, Washington TA, Greene NP. Mitochondrial degeneration precedes the development of muscle atrophy in progression of cancer cachexia in tumour-bearing mice. J Cachexia Sarcopenia Muscle 2017; 8:926-938. [PMID: 28845591 PMCID: PMC5700433 DOI: 10.1002/jcsm.12232] [Citation(s) in RCA: 170] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 06/16/2017] [Accepted: 07/14/2017] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Cancer cachexia is largely irreversible, at least via nutritional means, and responsible for 20-40% of cancer-related deaths. Therefore, preventive measures are of primary importance; however, little is known about muscle perturbations prior to onset of cachexia. Cancer cachexia is associated with mitochondrial degeneration; yet, it remains to be determined if mitochondrial degeneration precedes muscle wasting in cancer cachexia. Therefore, our purpose was to determine if mitochondrial degeneration precedes cancer-induced muscle wasting in tumour-bearing mice. METHODS First, weight-stable (MinStable) and cachectic (MinCC) ApcMin/+ mice were compared with C57Bl6/J controls for mRNA contents of mitochondrial quality regulators in quadriceps muscle. Next, Lewis lung carcinoma (LLC) cells or PBS (control) were injected into the hind flank of C57Bl6/J mice at 8 week age, and tumour allowed to develop for 1, 2, 3, or 4 weeks to examine time course of cachectic development. Succinate dehydrogenase stain was used to measure oxidative phenotype in tibialis anterior muscle. Mitochondrial quality and function were assessed using the reporter MitoTimer by transfection to flexor digitorum brevis and mitochondrial function/ROS emission in permeabilized adult myofibres from plantaris. RT-qPCR and immunoblot measured the expression of mitochondrial quality control and antioxidant proteins. Data were analysed by one-way ANOVA with Student-Newman-Kuels post hoc test. RESULTS MinStable mice displayed ~50% lower Pgc-1α, Pparα, and Mfn2 compared with C57Bl6/J controls, whereas MinCC exhibited 10-fold greater Bnip3 content compared with C57Bl6/J controls. In LLC, cachectic muscle loss was evident only at 4 weeks post-tumour implantation. Oxidative capacity and mitochondrial content decreased by ~40% 4 weeks post-tumour implantation. Mitochondrial function decreased by ~25% by 3 weeks after tumour implantation. Mitochondrial degeneration was evident by 2 week LLC compared with PBS control, indicated by MitoTimer red/green ratio and number of pure red puncta. Mitochondrial ROS production was elevated by ~50 to ~100% when compared with PBS at 1-3 weeks post-tumour implantation. Mitochondrial quality control was dysregulated throughout the progression of cancer cachexia in tumour-bearing mice. In contrast, antioxidant proteins were not altered in cachectic muscle wasting. CONCLUSIONS Functional mitochondrial degeneration is evident in LLC tumour-bearing mice prior to muscle atrophy. Contents of mitochondrial quality regulators across ApcMin/+ and LLC mice suggest impaired mitochondrial quality control as a commonality among pre-clinical models of cancer cachexia. Our data provide novel evidence for impaired mitochondrial health prior to cachectic muscle loss and provide a potential therapeutic target to prevent cancer cachexia.
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Rosa-Caldwell ME, Brown JL, Lee DE, Blackwell TA, Turner KW, Brown LA, Perry RA, Haynie WS, Washington TA, Greene NP. Autophagy activation, not peroxisome proliferator-activated receptor γ coactivator 1α, may mediate exercise-induced improvements in glucose handling during diet-induced obesity. Exp Physiol 2017. [PMID: 28639297 DOI: 10.1113/ep086406] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
NEW FINDINGS What is the central question of this study? What are the individual and combined effects of muscle-specific peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) overexpression and physical activity during high-fat feeding on glucose and exercise tolerance? What is the main finding and its importance? Our main finding is that muscle-specific PGC-1α overexpression provides no protection against lipid-overload pathologies nor does it enhance exercise adaptations. Instead, physical activity, regardless of PGC-1α content, protects against high-fat diet-induced detriments. Activation of muscle autophagy was correlated with exercise protection, suggesting that autophagy might be a mediating factor for exercise-induced protection from lipid overload. The prevalence of glucose intolerance is alarmingly high. Efforts to promote mitochondrial biogenesis through peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) to mitigate glucose intolerance have been controversial. However, physical activity remains a primary means to alleviate the condition. The aim of this study was to determine the combined effects of muscle-specific overexpression of PGC-1α and physical activity on glucose handling during diet-induced obesity. Wild-type (WT, ∼20) and PGC-1α muscle transgenic (MCK-PGC-1α, ∼20) mice were given a Western diet (WD) at 8 weeks age and allowed to consume food ab libitum throughout the study. At 12 weeks of age, all animals were divided into sedentary (SED) or voluntary wheel running (VWR) interventions. At 7, 11 and 15 weeks of age, animals underwent glucose tolerance tests (GTT) and graded exercise tests (GXT). At 16 weeks of age, tissues were collected. At 11 weeks, the MCK-PGC-1α animals had 50% greater glucose tolerance integrated area under the curve compared with WT. However, at 15 weeks, SED animals also had greater GTT integrated area under the curve compared with VWR, regardless of genotype; furthermore, SED animals demonstrated reduced exercise capacity compared with earlier time points, which was not seen in VWR animals. Voluntary distance run per day was correlated with GTT in VWR-WT, but not VWR-MCK-PGC-1α mice. Voluntary wheel running and genotype independently resulted in a greater LC3II/LC3I ratio, suggesting enhanced autophagosome formation, which was correlated with exercise-induced improvements in GTT. In conclusion, artificially increasing mitochondrial content does not protect from lipid-induced pathologies nor does it augment exercise adaptations. Physical activity ameliorates the effects of lipid overload-induced glucose intolerance, an effect that appears to be related to enhanced activation of autophagy.
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Perry RA, Haynie WS, Brown LA, Brown JL, Rosa-Caldwell ME, Lee DE, Baum JI, Smith-Blair N, Greene NP, Washington TA. The Combined Effect of Obesity & Pulmonary Arterial Hypertension on the Gastrocnemius in Zucker Rats. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000519142.94226.fb] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Blackwell TA, Brown JL, Lee DE, Rosa-Caldwell ME, Perry RA, Brown LA, Haynie WS, Wiggs MP, Washington TA, Greene NP. Myogenic And Atrophic Signaling In The Progression Of Cancer-cachexia. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000519042.94149.11] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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