Desmin Cytoskeleton Linked to Muscle Mitochondrial Distribution and Respiratory Function (original) (raw)
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Molecular approach to the regulation of mitochondrial function in oxidative muscle cells
2003
In saponin-skinned m uscle fibers from adult rat heart and m. soleus the apparent affinity o f the mitochondrial oxidative phosphorylation system for ADP (Km = 200-400 цМ) is much lower than in isolated mitochondria (Km = 10-20 цМ). This suggests a limited permeability o f the outer mitochondrial membrane (OMM) to adenine nucleotides in slow-twitch muscle cells. We have studied the postnatal changes in the affinity o f mitochondrial respiration for ADP, in relation to morphological alterations and expression o f mitochondrial creatine kinase (mi-CK) in rat heart in vivo. Analysis o f respiration o f skinned fibers revealed a gradual decrease in the apparent affinity o f mitochondria to ADP throughout 6 weeks post partum that indicates the development o f mechanism which increasingly limits the access o f ADP to mitochondria. The expression of mi-CK started between the 1st and 2nd weeks and reached the adult levels after 6 weeks. This process was associated with increases in creatine...
Study of regulation of mitochondrial respiration in vivo
Biochimica Et Biophysica Acta-bioenergetics, 1997
The purpose of this work was to investigate the mechanism of regulation of mitochondrial respiration in vivo in different muscles of normal rat and mice, and in transgenic mice deficient in desmin. Skinned fiber technique was used to study the mitochondrial respiration in the cells in vivo in the heart, soleus and white gastrocnemius skeletal muscles of these animals.
Effects of desmin gene knockout on mice heart mitochondria
Journal of bioenergetics and biomembranes, 2001
In heart tissue from mice lacking the intermediate filament (IF) desmin, mitochondria show an abnormal shape and distribution (Thornell et al., 1997). In the present study we have isolated heart mitochondria from desmin null (D-/-) and control (D+/+) mice, and analyzed their composition by SDS-PAGE, immunoblotting, and enzyme measurements. We found both in vitro and in situ that the conventional kinesin, the microtubule-associated plus-end directed motor, was frequently associated with D+/+ heart mitochondria, but not with D-/- heart mitochondria, suggesting that the positioning of mitochondria in heart is a dynamic event involving the IF desmin, the molecular motor kinesin, and, most likely, the microtubules (MT) network. Furthermore, an increased capacity in energy production was found, as indicated by a threefold higher creatine kinase activity in heart mitochondria from D-/- compared to D+/+ mice. We also observed a significantly lower amount of cytochrome c in heart mitochondri...
Biochimica et Biophysica Acta - Bioenergetics, 2014
The aim of this work was to study the regulation of respiration and energy fluxes in permeabilized oxidative and glycolytic skeletal muscle fibers, focusing also on the role of cytoskeletal protein tubulin βII isotype in mitochondrial metabolism and organization. By analyzing accessibility of mitochondrial ADP, using respirometry and pyruvate kinase-phosphoenolpyruvate trapping system for ADP, we show that the apparent affinity of respiration for ADP can be directly linked to the permeability of the mitochondrial outer membrane (MOM). Previous studies have shown that MOM permeability in cardiomyocytes can be regulated by VDAC interaction with cytoskeletal protein, βII tubulin. We found that in oxidative soleus skeletal muscle the high apparent K m for ADP is associated with low MOM permeability and high expression of non-polymerized βII tubulin. Very low expression of nonpolymerized form of βII tubulin in glycolytic muscles is associated with high MOM permeability for adenine nucleotides (low apparent K m for ADP).
Alterations in the heart mitochondrial proteome in a desmin null heart failure model
Journal of Molecular and Cellular Cardiology, 2005
Desmin, the major muscle-specific intermediate filament (IF) protein, is essential for mitochondrial behavior and function and maintenance of healthy muscle. Mice null for desmin develop dilated cardiomyopathy characterized by extensive cardiomyocyte death, fibrosis, calcification and eventual heart failure. We sought to investigate the heart mitochondrial proteome of wild type and desmin null mice in order to understand the cardiac and skeletal myopathy phenotype of desmin deficiency. The proteins were analyzed by 2-D electrophoresis, followed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Three hundred and eighty different gene products were identified, about 50% of which were enzyme subunits. Cytoskeletal and muscle-specific proteins, calcium-binding proteins, proteins with various other functions and about 70 unknown, hypothetical or poorly described gene products, were also identified. We have observed differences in most metabolic pathways, in apoptosis, calcium homeostasis, calcification and fibrosis and in different signaling pathways linked or not to mitochondrial function. The most significant changes were observed in ketone body and acetate metabolism, NADH shuttle proteins, amino-acid metabolism proteins and respiratory enzymes. Several of these changes are consistent with the known phenotype of desmin deficiency.
Cardiac, skeletal, and smooth muscle mitochondrial respiration: are all mitochondria created equal?
AJP: Heart and Circulatory Physiology, 2014
Park SY, Gifford JR, Andtbacka RH, Trinity JD, Hyngstrom JR, Garten RS, Diakos NA, Ives SJ, Dela F, Larsen S, Drakos S, Richardson RS. Cardiac, skeletal, and smooth muscle mitochondrial respiration: are all mitochondria created equal? Am J Physiol Heart Unlike cardiac and skeletal muscle, little is known about vascular smooth muscle mitochondrial respiration. Therefore, the present study examined mitochondrial respiratory rates in smooth muscle of healthy human feed arteries and compared with that of healthy cardiac and skeletal muscles. Cardiac, skeletal, and smooth muscles were harvested from a total of 22 subjects (53 Ϯ 6 yr), and mitochondrial respiration was assessed in permeabilized fibers. Complex I ϩ II, state 3 respiration, an index of oxidative phosphorylation capacity, fell progressively from cardiac to skeletal to smooth muscles (54 Ϯ 1, 39 Ϯ 4, and 15 Ϯ 1 pmol·s Ϫ1 ·mg Ϫ1 , P Ͻ 0.05, respectively). Citrate synthase (CS) activity, an index of mitochondrial density, also fell progressively from cardiac to skeletal to smooth muscles (222 Ϯ 13, 115 Ϯ 2, and 48 Ϯ 2 mol·g Ϫ1 ·min Ϫ1 , P Ͻ 0.05, respectively). Thus, when respiration rates were normalized by CS (respiration per mitochondrial content), oxidative phosphorylation capacity was no longer different between the three muscle types. Interestingly, complex I state 2 normalized for CS activity, an index of nonphosphorylating respiration per mitochondrial content, increased progressively from cardiac to skeletal to smooth muscles, such that the respiratory control ratio, state 3/state 2 respiration, fell progressively from cardiac to skeletal to smooth muscles (5.3 Ϯ 0.7, 3.2 Ϯ 0.4, and 1.6 Ϯ 0.3 pmol·s Ϫ1 ·mg Ϫ1 , P Ͻ 0.05, respectively). Thus, although oxidative phosphorylation capacity per mitochondrial content in cardiac, skeletal, and smooth muscles suggest all mitochondria are created equal, the contrasting respiratory control ratio and nonphosphorylating respiration highlight the existence of intrinsic functional differences between these muscle mitochondria. This likely influences the efficiency of oxidative phosphorylation and could potentially alter ROS production.
Human Molecular Genetics, 2007
Recent studies in desmin (À/À) mice have shown that the targeted ablation of desmin leads to pathological changes of the extrasarcomeric intermediate filament cytoskeleton, as well as structural and functional abnormalities of mitochondria in striated muscle. Here, we report on a novel heterozygous single adenine insertion mutation (c.5141_5143insA) in a 40-year-old patient with a distal myopathy. The insertion mutation leads to a frameshift and a truncated desmin (K239fs242). Using transfection studies in SW13 and BHK21 cells, we show that the K239fsX242 desmin mutant is incapable of forming a desmin intermediate filament network. Furthermore, it induces the collapse of a pre-existing desmin cytoskeleton, alters the subcellular distribution of mitochondria and leads to abnormal cytoplasmic protein aggregates reminiscent of desminimmunoreactive granulofilamentous material seen in the ultrastructural analysis of the patient's muscle. Analysis of mitochondrial function in isolated saponin-permeablized skeletal muscle fibres from our patient showed decreased maximal rates of respiration with the NAD-dependent substrate combination glutamate and malate, as well as a higher amytal sensitivity of respiration, indicating an in vivo inhibition of complex I activity. Our findings suggest that the heterozygous K239fsX242 desmin insertion mutation has a dominant negative effect on the polymerization process of desmin intermediate filaments and affects not only the subcellular distribution, but also biochemical properties of mitochondria in diseased human skeletal muscle. As a consequence, the intermediate filament pathology-induced mitochondrial dysfunction may contribute to the degeneration/regeneration process leading to progressive muscle dysfunction in human desminopathies. . Desmin, the main intermediate filament (IF) protein in skeletal and cardiac muscle cells, is a structural component of the extrasarcomeric cytoskeleton which forms a three-dimensional scaffold around myofibrillar Z-discs, thereby interlinking neighbouring myofibrils and connecting the
International Journal of Molecular Sciences, 2022
Analysis of the function, structure, and intracellular organization of mitochondria is important for elucidating energy metabolism and intracellular energy transfer. In addition, basic and clinically oriented studies that investigate organ/tissue/cell dysfunction in various human diseases, including myopathies, cardiac/brain ischemia-reperfusion injuries, neurodegenerative diseases, cancer, and aging, require precise estimation of mitochondrial function. It should be noted that the main metabolic and functional characteristics of mitochondria obtained in situ (in permeabilized cells and tissue samples) and in vitro (in isolated organelles) are quite different, thereby compromising interpretations of experimental and clinical data. These differences are explained by the existence of the mitochondrial network, which possesses multiple interactions between the cytoplasm and other subcellular organelles. Metabolic and functional crosstalk between mitochondria and extra-mitochondrial cel...
Heart Failure Affects Mitochondrial but Not Myofibrillar Intrinsic Properties of Skeletal Muscle
Circulation, 2000
Background —Congestive heart failure (CHF) induces abnormalities in skeletal muscle that are thought to in part explain exercise intolerance. The aim of the present study was to determine whether these changes actually result in contractile or metabolic functional alterations and whether they are muscle type specific. Methods and Results —With a rat model of CHF (induced by aortic banding), we studied mitochondrial function, mechanical properties, and creatine kinase (CK) compartmentation in situ in permeabilized fibers from soleus (SOL), an oxidative slow-twitch muscle, and white gastrocnemius (GAS), a glycolytic fast-twitch muscle. Animals were studied 7 months after surgery, and CHF was documented on the basis of anatomic data. Alterations in skeletal muscle phenotype were documented with an increased proportion of fast-type fiber and fast myosin heavy chain, decreased capillary-to-fiber ratio, and decreased citrate synthase activity. Despite a slow-to-fast phenotype transition i...
AJP: Regulatory, Integrative and Comparative Physiology, 2011
Past simulations of oxidative ATP metabolism in skeletal muscle have predicted that elimination of the creatine kinase (CK) reaction should result in dramatically faster oxygen consumption dynamics during transitions in ATP turnover rate. This hypothesis was investigated. Oxygen consumption of fast-twitch (FT) muscle isolated from wild-type (WT) and transgenic mice deficient in the myoplasmic (M) and mitochondrial (Mi) CK isoforms (MiM CK−/−) were measured at 20°C at rest and during electrical stimulation. MiM CK−/− muscle oxygen consumption activation kinetics during a step change in contraction rate were 30% faster than WT (time constant 53 ± 3 vs. 69 ± 4 s, respectively; mean ± SE, n = 8 and 6, respectively). MiM CK−/− muscle oxygen consumption deactivation kinetics were 380% faster than WT (time constant 74 ± 4 s vs. 264 ± 4 s, respectively). Next, the experiments were simulated using a computational model of the oxidative ATP metabolic network in FT muscle featuring ADP and Pi ...