scholarly journals Mitochondrial Function and Protein Turnover in the Diaphragm are Altered in LLC Tumor Model of Cancer Cachexia

2020 ◽  
Vol 21 (21) ◽  
pp. 7841
Author(s):  
Megan E. Rosa-Caldwell ◽  
Conner A. Benson ◽  
David E. Lee ◽  
Jacob L. Brown ◽  
Tyrone A. Washington ◽  
...  

It is established that cancer cachexia causes limb muscle atrophy and is strongly associated with morbidity and mortality; less is known about how the development of cachexia impacts the diaphragm. The purpose of this study was to investigate cellular signaling mechanisms related to mitochondrial function, reactive oxygen species (ROS) production, and protein synthesis during the development of cancer cachexia. C57BL/J6 mice developed Lewis Lung Carcinoma for either 0 weeks (Control), 1 week, 2 weeks, 3 weeks, or 4 weeks. At designated time points, diaphragms were harvested and analyzed. Mitochondrial respiratory control ratio was ~50% lower in experimental groups, which was significant by 2 weeks of cancer development, with no difference in mitochondrial content markers COXIV or VDAC. Compared to the controls, ROS was 4-fold elevated in 2-week animals but then was not different at later time points. Only one antioxidant protein, GPX3, was altered by cancer development (~70% lower in experimental groups). Protein synthesis, measured by a fractional synthesis rate, appeared to become progressively lower with the cancer duration, but the mean difference was not significant. The development and progression of cancer cachexia induces marked alterations to mitochondrial function and ROS production in the diaphragm and may contribute to increased cachexia-associated morbidity and mortality.

2020 ◽  
pp. jeb.236257
Author(s):  
Lucie Gerber ◽  
Kathy A. Clow ◽  
Anthony K. Gamperl

In fishes, the capacity of thermal acclimation to preserve cardiac mitochondrial function under future warming scenarios is important to understand given the central role that cardiac energy metabolism and performance play in this taxa's thermal tolerance. We acclimated Atlantic salmon to 12 and 20°C (for>2 months), and investigated the effects of acute and chronic warming on cardiac mitochondrial respiration and ROS production (release rate) using high-resolution fluorespirometry. Further, we compared the sensitivity of mitochondrial respiration to nitric oxide (i.e., the NO IC50), and assessed the mitochondrial response to anoxia-reoxygenation (AR). Acute exposure to 20°C increased maximal mitochondrial respiration by ∼55%, however, the mitochondria's complex I-respiratory control ratio was 17% lower and ROS production was increased by≥60%. Acclimation to 20°C: i) preserved mitochondrial coupling and aerobic capacity; ii) decreased the mitochondria's ROS production by ∼30%; iii) increased the mitochondria's NO IC50 by ∼23%; iv) and improved mitochondrial membrane integrity at 20°C. AR did not affect mitochondrial function at 12°C, but acute exposure to 20°C and AR depressed maximal mitochondrial respiration (by ∼9%) and coupling (by ∼16%) without impacting ROS production. Finally, warm acclimation did not improve the capacity of mitochondria to recover from AR, indicating that there was no ‘cross tolerance’ between these challenges. Our findings provide compelling evidence that thermal plasticity of cardiac mitochondrial function contributes to the Atlantic salmon's capability to survive at≥20°C for prolonged periods, but question whether this plasticity may allow them to withstand high temperatures when combined with other stressors.


Author(s):  
Vinaya Simha ◽  
Ian R Lanza ◽  
Surendra Dasari ◽  
Katherine A Klaus ◽  
Nathan Le Brasseur ◽  
...  

Abstract Background Familial Partial Lipodystrophy (FPL), Dunnigan variety is characterized by skeletal muscle hypertrophy and insulin resistance besides fat loss from the extremities. The cause for the muscle hypertrophy, and its functional consequences is not known. Objective To compare muscle strength and endurance, besides muscle protein synthesis rate between subjects with FPL and matched controls (n = 6 in each group). In addition, we studied skeletal muscle mitochondrial function and gene expression pattern to help understand the mechanisms for the observed differences. Methods Body composition by DEXA, insulin sensitivity by minimal modelling, assessment of peak muscle strength and fatigue, skeletal muscle biopsy and calculation of muscle protein synthesis rate, mitochondrial respirometry, skeletal muscle transcriptome, proteome and gene set enrichment analysis. Results Despite increased muscularity, FPL subjects did not demonstrate increased muscle strength but had earlier fatigue on chest press exercise. Decreased mitochondrial state 3 respiration in the presence of fatty acid substrate was noted, concurrent to elevated muscle lactate and decreased long-chain acylcarnitine. Based on gene transcriptome, there was significant down regulation of many critical metabolic pathways involved in mitochondrial biogenesis and function. Moreover, the overall pattern of gene expression was indicative of accelerated aging in FPL subjects. A lower muscle protein synthesis and down regulation of gene transcripts involved in muscle protein catabolism was observed. Conclusion Increased muscularity in FPL is not due to increased muscle protein synthesis and is likely due to reduced muscle protein degradation. Impaired mitochondrial function and altered gene expression likely explain the metabolic abnormalities and skeletal muscle dysfunction in FPL subjects.


2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
J Borger ◽  
D Scheiber ◽  
P Horn ◽  
D Pesta ◽  
U Boeken ◽  
...  

Abstract Background Alterations of mitochondrial function have been identified to play a role in Heart Failure (HF) pathophysiology. Oxidative phosphorylation (OXPHOS) capacity of the myocardium was shown to be reduced in the failing heart. Ineffective mitochondrial function promotes formation of reactive oxygen species (ROS) that may affect remodelling in ischemia. Thus far, human mitochondrial function comparing dilated cardiomyopathy (DCM) and ischemic cardiomyopathy (ICM) resembling the main aetiologies of heart failure with reduced ejection fraction (HFrEF) has not been investigated. Purpose We hypothesised that 1. ROS production is elevated in left ventricular myocardial tissue specimens of ICM patients compared to DCM. 2. Mitochondrial OXPHOS capacity is higher in left ventricular myocardial tissue specimens of DCM compared to ICM patients. Methods Myocardial tissue was obtained from the left ventricular apex from 63 patients (38 ICM, 25 DCM) with advanced HFrEF requiring implantation of a Left Ventricular Assist Device (LVAD). We performed high-resolution respirometry (HRR, OROBOROS Oxygraph-2k) in saponine-permeabilised myocardial fibres and measured ROS production fluoroscopically via the Amplex Red method. Statistical analysis was conducted using GraphPad Prism 7 and IBM SPSS v26.0. Results Groups were of comparable age (61.5±1.2 vs. 59.3±2.4 years, p=n.s.), sex (87% vs 85% male, p=n.s.), diabetic status (32% vs 38.4% type 2 diabetes mellitus, p=n.s.), and body mass index (28.1±0.8 vs. 26.3±1.1 kg/m2, p=n.s.). We detected reduced myocardial mitochondrial OXPHOS capacity in ICM under state 3 conditions by about 15% (68.7±34.0 vs. 80.9±30.5 pmol/(s*mg), p<0.05), after addition of Glutamate by 25% (78.9±38.7 vs. 104.8±41.2 pmol/(s*mg), p<0.01) as well as after Succinate (115.5±65.5 vs. 155±62.0 pmol/(s*mg), p<0.01), uncoupling agent FCCP (114.1±56.8 vs. 150.5±47.3 pmol/(s*mg), p<0.01), and by about 40% after addition of Complex I inhibitor Rotenone (55.5±25.9 vs. 96.9±28.0 pmol/(s*mg), p<0.001). We detected no difference in ROS production between ICM and DCM (0.6±0.05 vs. 0.76±0.08 pmol/(s*ml), p=n.s.). Conclusion This is the first human study deciphering distinct alterations in mitochondrial function (OXPHOS capacity) in ventricular myocardium of HFrEF patients. Future studies may address how distinct metabolic patterns at the time of implantation may relate to long-term outcome of HFrEF in terms of remodelling and recovery. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): DFG (German Research Foundation)


2015 ◽  
Vol 173 (1) ◽  
pp. R25-R34 ◽  
Author(s):  
Jorn Trommelen ◽  
Bart B L Groen ◽  
Henrike M Hamer ◽  
Lisette C P G M de Groot ◽  
Luc J C van Loon

BackgroundThough it is well appreciated that insulin plays an important role in the regulation of muscle protein metabolism, there is much discrepancy in the literature on the capacity of exogenous insulin administration to increase muscle protein synthesis ratesin vivoin humans.ObjectiveTo assess whether exogenous insulin administration increases muscle protein synthesis rates in young and older adults.DesignA systematic review of clinical trials was performed and the presence or absence of an increase in muscle protein synthesis rate was reported for each individual study arm. In a stepwise manner, multiple models were constructed that excluded study arms based on the following conditions: model 1, concurrent hyperaminoacidemia; model 2, insulin-induced hypoaminoacidemia; model 3, supraphysiological insulin concentrations; and model 4, older, more insulin resistant, subjects.ConclusionsFrom the presented data in the current systematic review, we conclude that: i) exogenous insulin and amino acid administration effectively increase muscle protein synthesis, but this effect is attributed to the hyperaminoacidemia; ii) exogenous insulin administered systemically induces hypoaminoacidemia which obviates any insulin-stimulatory effect on muscle protein synthesis; iii) exogenous insulin resulting in supraphysiological insulin levels exceeding 50 000 pmol/l may effectively augment muscle protein synthesis; iv) exogenous insulin may have a diminished effect on muscle protein synthesis in older adults due to age-related anabolic resistance; and v) exogenous insulin administered systemically does not increase muscle protein synthesis in healthy, young adults.


1989 ◽  
Vol 9 (1) ◽  
pp. 87-95 ◽  
Author(s):  
Michihiro Kirikae ◽  
Mirko Diksic ◽  
Y. Lucas Yamamoto

We examined the rate of glucose utilization and the rate of valine incorporation into proteins using 2-[18F]fluoro-2-deoxyglucose and L-[1-14C]-valine in a rat brain tumor model by quantitative double-tracer autoradiography. We found that in the implanted tumor the rate of valine incorporation into proteins was about 22 times and the rate of glucose utilization was about 1.5 times that in the contralateral cortex. (In the ipsilateral cortex, the tumor had a profound effect on glucose utilization but no effect on the rate of valine incorporation into proteins.) Our findings suggest that it is more useful to measure protein synthesis than glucose utilization to assess the effectiveness of antitumor agents and their toxicity to normal brain tissue. We compared two methods to estimate the rate of valine incorporation: “kinetic” (quantitation done using an operational equation and the average brain rate coefficients) and “washed slices” (unbound labeled valine removed by washing brain slices in 10% thrichloroacetic acid). The results were the same using either method. It would seem that the kinetic method can thus be used for quantitative measurement of protein synthesis in brain tumors and normal brain tissue using [11C]-valine with positron emission tomography.


2013 ◽  
Vol 91 (8) ◽  
pp. 593-600 ◽  
Author(s):  
Oana M. Duicu ◽  
Silvia N. Mirica ◽  
Dorina E. Gheorgheosu ◽  
Andreea I. Privistirescu ◽  
Ovidiu Fira-Mladinescu ◽  
...  

It is widely recognized that mitochondrial dysfunction is a key component of the multifactorial process of ageing. The effects of age on individual components of mitochondrial function vary across species and strains. In this study we investigated the oxygen consumption, the mitochondrial membrane potential (Δψ), the sensitivity of mitochondrial permeability transition pore (mPTP) to calcium overload, and the production of reactive oxygen species (ROS) in heart mitochondria isolated from old compared with adult healthy Sprague–Dawley rats. Respirometry studies and Δψ measurements were performed with an Oxygraph-2k equipped with a tetraphenylphosphonium electrode. ROS production and calcium retention capacity were measured spectrofluorimetrically. Our results show an important decline for all bioenergetic parameters for both complex I and complex II supported-respiration, a decreased Δψ in mitochondria energized with complex I substrates, and an increased mitochondrial ROS production in the old compared with the adult group. Mitochondrial sensitivity to Ca2+-induced mPTP opening was also increased in the old compared with the adult animals. Moreover, the protective effect of cyclosporine A on mPTP opening was significantly reduced in the old group. We conclude that healthy ageing is associated with a decrease in heart mitochondria function in Sprague–Dawley rats.


1988 ◽  
Vol 255 (2) ◽  
pp. E166-E172 ◽  
Author(s):  
M. M. Jepson ◽  
P. C. Bates ◽  
P. Broadbent ◽  
J. M. Pell ◽  
D. J. Millward

Muscle glutamine concentration ([GLN]) and protein synthesis rate (Ks) have been examined in vivo in well-fed, protein-deficient, starved, and endotoxemic rats. With protein deficiency (8 or 5% casein diet), [GLN] fell from 7.70 to 5.58 and 3.56 mmol/kg in the 8 and 5% diet groups, with Ks falling from 15.42 to 9.1 and 6.84%/day. Three-day starvation reduced [GLN] and Ks to 2.38 mmol/kg and 5.6%/day, respectively. In all these groups food intakes and insulin were generally well maintained (except in the starved group), whereas free 3,5,3'-triiodothyronine (T3) was depressed in the starved and 5% protein group. The E. coli lipopolysaccharide endotoxin (3 mg/kg) reduced [GLN] to 5.85 and 4.72 mmol/kg and Ks to 10.5 and 9.10%/day in two well-fed groups. Insulin levels were increased, and free T3 levels fell. Combined protein deficiency and endotoxemia further reduced [GLN] and Ks to 1.88 mmol/kg and 4.01%/day, respectively, in the 5% protein rats. Changes in both ribosomal activity (KRNA) and concentration (RNA/protein) contributed to the fall in Ks in malnutrition and endotoxemia, although reductions in the RNA concentration were most marked with protein deficiency and reductions in the KRNA dominated the response to the endotoxin. The changes in [GLN] and Ks were highly correlated as were [GLN] and both KRNA and the RNA concentration, and these relationships were unique to glutamine. These relationships could reflect sensitivity of glutamine transport and protein synthesis to the same regulatory influences, and the particular roles of insulin and T3 are discussed, as well as any direct influence of glutamine on protein synthesis.


2009 ◽  
Vol 55 (1) ◽  
pp. 75-80 ◽  
Author(s):  
Kazuyo TUJIOKA ◽  
Miho OHSUMI ◽  
Kenji HORIE ◽  
Mujo KIM ◽  
Kazutoshi HAYASE ◽  
...  

1978 ◽  
Vol 235 (2) ◽  
pp. E165 ◽  
Author(s):  
J C Waterlow ◽  
M H Golden ◽  
P J Garlick

Whole-body protein synthesis was measured with [15N]glycine in malnourished and recovered infants and in obese patients. Comparisons were made: 1) between results obtained with single (S) and repeated (R) oral dosage of tracer; and 2) between urea and ammonia as end products. In the infants S and R gave similar values for the synthesis rate. With both methods of dosage, the values obtained with NH3 as end product were about two-thirds of those with urea. It is suggested that the cause of this result is that glycine contributes preferentially to the formation of urinary NH3. With NH3 as end product, a collection period of 12 h has been found to be suitable. With urea it is not possible to define an appropriate collection period. The combination of single dose of [15N]glycine with urinary NH3 as end product provides a simple method for measuring whole-body protein synthesis under clinical and field conditions. It can be repeated at short intervals and can give useful comparative information provided that conditions are carefully standardized. The reproducibility so far is +/- 13%.


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