Mitochondrial Bionergetics

This white paper presents a unified hypothesis merging Sheppardʼs Universal Proxy Theory (SUPT) and Emily Newtonʼs harmonic cosmology, proposing that mitochondrial activity functions as a biologically embedded interface for dimensional plasma resonance. Crop circle phenomena are reframed as harmonic plasma imprints, projected through scalar coherence windows via electromagnetic alignment, primarily centered around the 377 Hz resonance node. This model bridges atomic, biological, solar, and geometric harmonic expressions into a functional convergence point for experimental biophysics, astrophysical validation, and consciousness studies.

Mitochondria are intracellular organelles, which provide cells with energy and participate in mul tiple processes of cell vital functions. Within one of the numerous theories of aging, dysfunction of mitochon dria is considered to lead to tissue degeneration and induce the initial stage in developing of degenerative dis eases. Since mitochondria play a clue role in apoptosis/necrosis processes, it was suggested that dysfunction of mitochondria observed under aging is related with disturbance of programmed cell death regulation. In the present study, a comparative examination of parameters of the functional states of mitochondria isolated from young (2-3 months old) and old (20-22 months old) rats under conditions of opening of unselective pore (PTP, permeability transition pore) has been performed. Ca 2+ accumulation rate in mitochondria isolated from old rats was found to be decreased by 25-30%, threshold calcium concentration was lowered to 50%, and the swelling of mitochondria loaded by calcium was stimulated 3-4 fold. Production of reactive oxygen species (ROS) has been also determined in these mitochondria. In old mitochondria superoxide anion level was increased. In addition, H 2 O 2 content was found to be 2 times higher in mitochondria with PTP opened. Using electron microscopy method, a decreased amount of cristae in mitochondria was revealed under aging.

High Altitude Pulmonary Edema (HAPE) is a threatening disorder caused due to acute exposure to high altitude above 3000 m. Apart from multiple factors involved, the genetic factors also play an important function in the pathogenesis of HAPE. This study aims to evaluate the role of mtDNA polymorphism and their association with haplogroup in understanding the etiology of HAPE. In this study, all the HAPE susceptible and acclimatized control subjects could be classified into nine haplogroups pertaining mostly to Macrohaplogroup M and U. The frequency of haplogroup M was significantly higher in HAPE susceptibles whereas the haplogroup M33a2′3 was found only in HAPE susceptibles. The variant G4491A and A4944G of MT-ND2, A14002G of MT-ND5, and C8562T of MT-ATP8, were definition site of haplogroup M33a2′3. The frequency of A10398G of MT-ND3, A8701G of MT-ATP6 and C14766T of MT-CYB genes were significantly higher in HAPE susceptibles. mtDNA copy number also plays a significant synergistic r...

Coenzyme Q 10 deficiency is a clinically and genetically heterogeneous disorder, with manifestations that may range from fatal neonatal multisystem failure, to adult-onset encephalopathy. We report a patient who presented at birth with severe lactic acidosis, proteinuria, dicarboxylic aciduria, and hepatic insufficiency. She also had dilation of left ventricle on echocardiography. Her neurological condition rapidly worsened and despite aggressive care she died at 23 h of life. Muscle histology displayed lipid accumulation. Electron microscopy showed markedly swollen mitochondria with fragmented cristae. Respiratory-chain enzymatic assays showed a reduction of combined activities of complex I+III and II+III with normal activities of isolated complexes. The defect was confirmed in fibroblasts, where it could be rescued by supplementing the culture medium with 10 μM coenzyme Q 10 . Coenzyme Q 10 levels were reduced (28% of controls) in these cells. We performed exome sequencing and focused the analysis on genes involved in coenzyme Q 10 biosynthesis. The patient harbored a homozygous c.545T4G, p.(Met182Arg) alteration in COQ2, which was validated by functional complementation in yeast. In this case the biochemical and morphological features were essential to direct the genetic diagnosis. The parents had another pregnancy after the biochemical diagnosis was established, but before the identification of the genetic defect. Because of the potentially high recurrence risk, and given the importance of early CoQ 10 supplementation, we decided to treat with CoQ 10 the newborn child pending the results of the biochemical assays. Clinicians should consider a similar management in siblings of patients with CoQ10 deficiency without a genetic diagnosis.

The permeability transition pore (PTP) is a large channel of the mitochondrial inner membrane, the opening of which is the central event in many types of stress-induced cell death. PTP opening is induced by elevated concentrations of mitochondrial calcium. It has been demonstrated that spermine and other polyamines can delay calcium-induced swelling of isolated mitochondria, suggesting their role as inhibitors of the mitochondrial PTP. Here we further investigated the mechanism by which spermine inhibits the calcium-induced, cyclosporine A (CSA)sensitive PTP by using three indicators: 1) calcium release from the mitochondria detected with calcium green, 2) mitochondrial membrane depolarization using TMRM, and 3) mitochondrial swelling by measuring light absorbance. We found that despite calcium release and membrane depolarization, indicative of PTP activation, mitochondria underwent only partial swelling in the presence of spermine. This was in striking contrast to the high-amplitude swelling detected in control mitochondria and in mitochondria treated with the PTP inhibitor CSA. We conclude that spermine selectively prevents opening of the high-conductance state, while allowing activation of the lower conductance state of the PTP. We propose that the existence of lower conductance, stressinduced PTP might play an important physiological role, as it is expected to allow the release of toxic levels of calcium, while keeping important molecules (e.g., NAD) within the mitochondrial matrix.

Lactate, the conjugate base of lactic acid occurring in aqueous biological fluids, has been derided as a "dead-end" waste product of anaerobic metabolism. Catalyzed by the near-equilibrium enzyme lactate dehydrogenase (LDH), the reduction of pyruvate to lactate is thought to serve to regenerate the NAD + necessary for continued glycolytic flux. Reaction kinetics for LDH imply that lactate oxidation is rarely favored in the tissues of its own production. However, a substantial body of research directly contradicts any notion that LDH invariably operates unidirectionally in vivo. In the current Perspective, a model is forwarded in which the continuous formation and oxidation of lactate serves as a mitochondrial electron shuttle, whereby lactate generated in the cytosol of the cell is oxidized at the mitochondria of the same cell. From this perspective, an intracellular lactate shuttle operates much like the malate-aspartate shuttle (MAS); it is also proposed that the two shuttles are necessarily interconnected in a lactate-MAS. Among the requisite features of such a model, significant compartmentalization of LDH, much like the creatine kinase of the phosphocreatine shuttle, would facilitate net cellular lactate oxidation in a variety of cell types.

Coenzyme Q 10 deficiency is a clinically and genetically heterogeneous disorder, with manifestations that may range from fatal neonatal multisystem failure, to adult-onset encephalopathy. We report a patient who presented at birth with severe lactic acidosis, proteinuria, dicarboxylic aciduria, and hepatic insufficiency. She also had dilation of left ventricle on echocardiography. Her neurological condition rapidly worsened and despite aggressive care she died at 23 h of life. Muscle histology displayed lipid accumulation. Electron microscopy showed markedly swollen mitochondria with fragmented cristae. Respiratory-chain enzymatic assays showed a reduction of combined activities of complex I+III and II+III with normal activities of isolated complexes. The defect was confirmed in fibroblasts, where it could be rescued by supplementing the culture medium with 10 μM coenzyme Q 10. Coenzyme Q 10 levels were reduced (28% of controls) in these cells. We performed exome sequencing and focused the analysis on genes involved in coenzyme Q 10 biosynthesis. The patient harbored a homozygous c.545T4G, p.(Met182Arg) alteration in COQ2, which was validated by functional complementation in yeast. In this case the biochemical and morphological features were essential to direct the genetic diagnosis. The parents had another pregnancy after the biochemical diagnosis was established, but before the identification of the genetic defect. Because of the potentially high recurrence risk, and given the importance of early CoQ 10 supplementation, we decided to treat with CoQ 10 the newborn child pending the results of the biochemical assays. Clinicians should consider a similar management in siblings of patients with CoQ10 deficiency without a genetic diagnosis.

Once thought to be a waste product of anaerobic metabolism, lactate is now known to form continuously under aerobic conditions. Shuttling between producer and consumer cells fulfills at least three purposes for lactate: (1) a major energy source, (2) the major gluconeogenic precursor, and (3) a signaling molecule. ''Lactate shuttle'' (LS) concepts describe the roles of lactate in delivery of oxidative and gluconeogenic substrates as well as in cell signaling. In medicine, it has long been recognized that the elevation of blood lactate correlates with illness or injury severity. However, with lactate shuttle theory in mind, some clinicians are now appreciating lactatemia as a ''strain'' and not a ''stress'' biomarker. In fact, clinical studies are utilizing lactate to treat pro-inflammatory conditions and to deliver optimal fuel for working muscles in sports medicine. The above, as well as historic and recent studies of lactate metabolism and shuttling, are discussed in the following review.

Coenzyme Q 10 deficiency is a clinically and genetically heterogeneous disorder, with manifestations that may range from fatal neonatal multisystem failure, to adult-onset encephalopathy. We report a patient who presented at birth with severe lactic acidosis, proteinuria, dicarboxylic aciduria, and hepatic insufficiency. She also had dilation of left ventricle on echocardiography. Her neurological condition rapidly worsened and despite aggressive care she died at 23 h of life. Muscle histology displayed lipid accumulation. Electron microscopy showed markedly swollen mitochondria with fragmented cristae. Respiratory-chain enzymatic assays showed a reduction of combined activities of complex I+III and II+III with normal activities of isolated complexes. The defect was confirmed in fibroblasts, where it could be rescued by supplementing the culture medium with 10 μM coenzyme Q 10. Coenzyme Q 10 levels were reduced (28% of controls) in these cells. We performed exome sequencing and focused the analysis on genes involved in coenzyme Q 10 biosynthesis. The patient harbored a homozygous c.545T4G, p.(Met182Arg) alteration in COQ2, which was validated by functional complementation in yeast. In this case the biochemical and morphological features were essential to direct the genetic diagnosis. The parents had another pregnancy after the biochemical diagnosis was established, but before the identification of the genetic defect. Because of the potentially high recurrence risk, and given the importance of early CoQ 10 supplementation, we decided to treat with CoQ 10 the newborn child pending the results of the biochemical assays. Clinicians should consider a similar management in siblings of patients with CoQ10 deficiency without a genetic diagnosis.

Although mitochondrial Ca 2+ overload and ROS production play a critical role in mitochondriamediated cell death, a cause-effect relationship between them remains elusive. This study elucidated the crosstalk between mitochondrial swelling, ROS production, and electron transfer chain (ETC) supercomplexes in rat heart mitochondria in response to Ca 2+ and tert-butyl hydroperoxide (TBH), a lipid-soluble organic peroxide. Results showed that ROS production induced by TBH was significantly increased in the presence of Ca 2+ in a dose-dependent manner. TBH markedly inhibited the state 3 respiration rate with no effect on the mitochondrial swelling. Ca 2+ exerted a slight effect on mitochondrial respiration that was greatly aggravated by TBH. Analysis of supercomplexes revealed a minor difference in the presence of TBH and/or Ca 2+. However, incubation of mitochondria in the presence of high Ca 2+ (1 mM) or inhibitors of ETC complexes (rotenone and antimycin A) induced disintegration of the main supercomplex, respirasome. Thus, PTP-dependent swelling of mitochondria solely depends on Ca 2+ but not ROS. TBH has no effect on the respirasome while Ca 2+ induces disintegration of the supercomplex only at a high concentration. Intactness of individual ETC complexes I and III is important for maintenance of the structural integrity of the respirasome.

Recent evidence highlights that the cancer cell energy requirements vary greatly from normal cells and that cancer cells exhibit different metabolic phenotypes with variable participation of both glycolysis and oxidative phosphorylation. NADH-ubiquinone oxidoreductase (Complex I) is the largest complex of the mitochondrial electron transport chain and contributes about 40% of the proton motive force required for mitochondrial ATP synthesis. In addition, Complex I plays an essential role in biosynthesis and redox control during proliferation, resistance to cell death, and metastasis of cancer cells. Although knowledge about the structure and assembly of Complex I is increasing, information about the role of Complex I subunits in tumorigenesis is scarce and contradictory. Several small molecule inhibitors of Complex I have been described as selective anticancer agents; however, pharmacologic and genetic interventions on Complex I have also shown pro-tumorigenic actions, involving diff...

We previously reported that hypoxia-inducible factor (HIF)-1 inhibitor LW6, an aryloxyacetylamino benzoic acid derivative, inhibits malate dehydrogenase 2 (MDH2) activity during the mitochondrial tricarboxylic acid (TCA) cycle. In this study, we present a novel MDH2 inhibitor compound 7 containing benzohydrazide moiety, which was identified through structure-based virtual screening of chemical library. Similar to LW6, compound 7 inhibited MDH2 activity in a competitive fashion, thereby reducing NADH level. Consequently, compound 7 reduced oxygen consumption and ATP production during the mitochondrial respiration cycle, resulting in increased intracellular oxygen concentration. Therefore, compound 7 suppressed the accumulation of HIF-1α and expression of its target genes, vascular endothelial growth factor (VEGF) and glucose transporter 1 (GLUT1). Moreover, reduction in ATP content activated AMPK, thereby inactivating ACC and mTOR the downstream pathways. As expected, compound 7 exhi...

Coenzyme Q 10 deficiency is a clinically and genetically heterogeneous disorder, with manifestations that may range from fatal neonatal multisystem failure, to adult-onset encephalopathy. We report a patient who presented at birth with severe lactic acidosis, proteinuria, dicarboxylic aciduria, and hepatic insufficiency. She also had dilation of left ventricle on echocardiography. Her neurological condition rapidly worsened and despite aggressive care she died at 23 h of life. Muscle histology displayed lipid accumulation. Electron microscopy showed markedly swollen mitochondria with fragmented cristae. Respiratory-chain enzymatic assays showed a reduction of combined activities of complex I+III and II+III with normal activities of isolated complexes. The defect was confirmed in fibroblasts, where it could be rescued by supplementing the culture medium with 10 μM coenzyme Q 10. Coenzyme Q 10 levels were reduced (28% of controls) in these cells. We performed exome sequencing and focused the analysis on genes involved in coenzyme Q 10 biosynthesis. The patient harbored a homozygous c.545T4G, p.(Met182Arg) alteration in COQ2, which was validated by functional complementation in yeast. In this case the biochemical and morphological features were essential to direct the genetic diagnosis. The parents had another pregnancy after the biochemical diagnosis was established, but before the identification of the genetic defect. Because of the potentially high recurrence risk, and given the importance of early CoQ 10 supplementation, we decided to treat with CoQ 10 the newborn child pending the results of the biochemical assays. Clinicians should consider a similar management in siblings of patients with CoQ10 deficiency without a genetic diagnosis.

Lactate (La−) has long been at the center of controversy in research, clinical, and athletic settings. Since its discovery in 1780, La− has often been erroneously viewed as simply a hypoxic waste product with multiple deleterious effects. Not until the 1980s, with the introduction of the cell-to-cell lactate shuttle did a paradigm shift in our understanding of the role of La− in metabolism begin. The evidence for La− as a major player in the coordination of whole-body metabolism has since grown rapidly. La− is a readily combusted fuel that is shuttled throughout the body, and it is a potent signal for angiogenesis irrespective of oxygen tension. Despite this, many fundamental discoveries about La− are still working their way into mainstream research, clinical care, and practice. The purpose of this review is to synthesize current understanding of La− metabolism via an appraisal of its robust experimental history, particularly in exercise physiology. That La− production increases during dysoxia is beyond debate, but this condition is the exception rather than the rule. Fluctuations in blood [La−] in health and disease are not typically due to low oxygen tension, a principle first demonstrated with exercise and now understood to varying degrees across disciplines. From its role in coordinating whole-body metabolism as a fuel to its role as a signaling molecule in tumors, the study of La− metabolism continues to expand and holds potential for multiple clinical applications. This review highlights La−'s central role in metabolism and amplifies our understanding of past research.

The permeability transition pore (PTP) is a large channel of the mitochondrial inner membrane, the opening of which is the central event in many types of stress-induced cell death. PTP opening is induced by elevated concentrations of mitochondrial calcium. It has been demonstrated that spermine and other polyamines can delay calcium-induced swelling of isolated mitochondria, suggesting their role as inhibitors of the mitochondrial PTP. Here we further investigated the mechanism by which spermine inhibits the calcium-induced, cyclosporine A (CSA) - sensitive PTP by using three indicators: 1) calcium release from the mitochondria detected with calcium green, 2) mitochondrial membrane depolarization using TMRM, and 3) mitochondrial swelling by measuring light absorbance. We found that despite calcium release and membrane depolarization, indicative of PTP activation, mitochondria underwent only partial swelling in the presence of spermine. This was in striking contrast to the high-ampli...

Lactate, the conjugate base of lactic acid occurring in aqueous biological fluids, has been derided as a "dead-end" waste product of anaerobic metabolism. Catalyzed by the near-equilibrium enzyme lactate dehydrogenase (LDH), the reduction of pyruvate to lactate is thought to serve to regenerate the NAD + necessary for continued glycolytic flux. Reaction kinetics for LDH imply that lactate oxidation is rarely favored in the tissues of its own production. However, a substantial body of research directly contradicts any notion that LDH invariably operates unidirectionally in vivo. In the current Perspective, a model is forwarded in which the continuous formation and oxidation of lactate serves as a mitochondrial electron shuttle, whereby lactate generated in the cytosol of the cell is oxidized at the mitochondria of the same cell. From this perspective, an intracellular lactate shuttle operates much like the malate-aspartate shuttle (MAS); it is also proposed that the two shuttles are necessarily interconnected in a lactate-MAS. Among the requisite features of such a model, significant compartmentalization of LDH, much like the creatine kinase of the phosphocreatine shuttle, would facilitate net cellular lactate oxidation in a variety of cell types.

Nutritional status, in particular overweight and obesity, as well as sedentarism and high-fat diet consumption, are important risk factors to develop chronic diseases, which have a higher impact on the elderly’s health. Therefore, these nutritional problems have become a concern to human healthspan and longevity. The fatty acids obtained thru the diet or due to fatty acid synthesis during obesity accumulate within the body generating toxicity and cell death. Fat is not only stored in adipose tissue, but it can also be stored in skeletal muscle. Palmitic acid (PA) has been reported as one of the most important saturated free fatty acids; it is associated to chronic oxidative stress and increased mitochondrial ROS production causing cell death by apoptosis. In skeletal muscle, palmitate has been associated with various pathophysiological consequences, which lead to muscle deterioration during aging and obesity. Since molecules that modify redox state have been proven to prevent cellul...

Nutritional status, in particular overweight and obesity, as well as sedentarism and high-fat diet consumption, are important risk factors to develop chronic diseases, which have a higher impact on the elderly’s health. Therefore, these nutritional problems have become a concern to human healthspan and longevity. The fatty acids obtained thru the diet or due to fatty acid synthesis during obesity accumulate within the body generating toxicity and cell death. Fat is not only stored in adipose tissue, but it can also be stored in skeletal muscle. Palmitic acid (PA) has been reported as one of the most important saturated free fatty acids; it is associated to chronic oxidative stress and increased mitochondrial ROS production causing cell death by apoptosis. In skeletal muscle, palmitate has been associated with various pathophysiological consequences, which lead to muscle deterioration during aging and obesity. Since molecules that modify redox state have been proven to prevent cellul...

After a Century it is time to turn the page on understanding of lactate metabolism and appreciate that lactate shuttling as an important component of intermediary metabolism in vivo. Cell-Cell and intracellular Lactate Shuttles fulfill purposes of energy substrate production and distribution as well as cell signaling under fully aerobic conditions. Recognition of lactate shuttling came first in studies of physical exercise where roles of driver and recipient cells and tissues were obvious. Moreover, the presence of lactate shuttling as part of postprandial glucose disposal has been recognized. Mitochondrial respiration creates the physiological sink for lactate disposal in vivo. Repeated lactate exposure from regular exercise results in adaptive processes such as mitochondrial biogenesis and other healthful circulatory and neurological characteristic such as improved physical work capacity, metabolic flexibility and cognition. The importance of lactate and lactate shuttling in healt...

The nature and existence of mitochondrial lactate oxidation is debated in the literature. Obscuring the issue are disparate findings in isolated mitochondria, as well as relatively low rates of lactate oxidation observed in permeabilized muscle fibres. However, respiration with lactate has yet to be directly assessed in brain tissue with the mitochondrial reticulum intact. To determine whether lactate is oxidized in the matrix of brain mitochondria, oxygen consumption was measured in saponin-permeabilized mouse brain cortex samples, and rat prefrontal cortex and hippocampus (dorsal) subregions. While respiration in the presence of ADP and malate increased with the addition of lactate, respiration was maximized following the addition of exogenous NAD<sup>+</sup>, suggesting maximal lactate metabolism involves extra-matrix lactate dehydrogenase. This was further supported when NAD<sup>+</sup>-dependent lactate oxidation was significantly decreased with the addi...

F-ATP synthase is a leading candidate as the mitochondrial permeability transition pore (PTP) but the mechanism(s) leading to channel formation remain undefined. Here, to shed light on the structural requirements for PTP formation, we test cells ablated for g, OSCP and b subunits, and ρ0 cells lacking subunits a and A6L. Δg cells (that also lack subunit e) do not show PTP channel opening in intact cells or patch-clamped mitoplasts unless atractylate is added. Δb and ΔOSCP cells display currents insensitive to cyclosporin A but inhibited by bongkrekate, suggesting that the adenine nucleotide translocator (ANT) can contribute to channel formation in the absence of an assembled F-ATP synthase. Mitoplasts from ρ0 mitochondria display PTP currents indistinguishable from their wild-type counterparts. In this work, we show that peripheral stalk subunits are essential to turn the F-ATP synthase into the PTP and that the ANT provides mitochondria with a distinct permeability pathway.

F-ATP synthase is a leading candidate as the mitochondrial permeability transition pore (PTP) but the mechanism(s) leading to channel formation remain undefined. Here, to shed light on the structural requirements for PTP formation, we test cells ablated for g, OSCP and b subunits, and ρ0 cells lacking subunits a and A6L. Δg cells (that also lack subunit e) do not show PTP channel opening in intact cells or patch-clamped mitoplasts unless atractylate is added. Δb and ΔOSCP cells display currents insensitive to cyclosporin A but inhibited by bongkrekate, suggesting that the adenine nucleotide translocator (ANT) can contribute to channel formation in the absence of an assembled F-ATP synthase. Mitoplasts from ρ0 mitochondria display PTP currents indistinguishable from their wild-type counterparts. In this work, we show that peripheral stalk subunits are essential to turn the F-ATP synthase into the PTP and that the ANT provides mitochondria with a distinct permeability pathway.

Mitochondria provide cellular energy through oxidative phosphorylation, but as an integral part of this process, superoxides and other reactive
oxygen species (ROS) are also produced. When the balance between the production of free radicals and antioxidant capacity of the cardiac cells
altered, oxidative stress is induced. Oxidative stress has been linked to the development of ischemic heart disease, atherosclerosis, congestive heart
failure, ischemic-reperfusion injury, and vascular endothelial dysfunction. Although several clinical trials over the past decades employed different
strategies of antioxidants supplementation, the results were generally negative in the setting of chronic preventative therapy. Less attention has
been paid to the modulation of ROS production, despite the fact that prevention, rather than cure, would appear to be the logic approach to attenuate
the oxidative damage. There is increasing evidence that endogenous myocardial uncoupling proteins (UCPs) can play a vital role in regulating ROS
generation to protect against various pathogenic stresses. Their expression, which can be induced, may well be a potential therapeutic target for
various drugs to alleviate the harmful effects of pathogenic processes and hence modify the progression of cardiovascular diseases (CVDs).
Myocardial function depends on the energy that it is able to synthesize and transfer in the form of energy-rich energy for phosphate bonds to
fuel excitation-contraction coupling. More than 90% of cardiac cells energy is produced in the mitochondria from oxidative phosphorylation activity
[1]. Oxidative phosphorylation is the process by which energy from fuel oxidation is converted to the high-energy phosphate bonds of adenosine
triphosphate (ATP). The chemiosmotic hypothesis suggests that the ATP synthesis is provided by the electrochemical gradient across the inner
mitochondrial membrane. This electrochemical gradient is maintained by constituents of the electron transport chain (ETC), which acts to pump
protons from the mitochondrial matrix to the intermembrane space of the mitochondria as they accept and donate electrons in a prescribed manner
Figure. This process of electron transport and oxidative metabolism in cardiac cells are accompanied by the reduction of oxygen to superoxide and
other ROS which considered as a by-product of mitochondrial respiration.

Neurons invest considerable energy in the generation and maintenance of a steep electrochemical Na + gradient across the plasma membrane. The Na + gradient is in turn used for various housekeeping tasks, including import of nutrients, export of waste, volume and pH regulation, and modulation of Ca 2+ signaling. In addition, neurons make intensive use of the Na + gradient to transmit information by membrane depolarization, to the extent that in these cells the Na + /K + ATPase pump accounts for over 80% of the ATP turnover. Almost all ATP is produced in mitochondria, so how does the organelle know how much to produce and when? This is a central question in bioenergetics. Ever since the studies of isolated mitochondria by Britton Chance and colleagues in the hay days of cybernetics and feedback control theory, the coupling between energy demand and supply has been assigned to ADP [1]. Later on Krebs cycle dehydrogenases and other mitochondrial enzymes were found to be sensitive to Ca 2+ [2, 3], suggesting an additional coupling mechanism.

Cuprizone affects the liver of treated mice in a random manner, causing no appreciable change in some cases and inducing the formation of megamitochondria with altered properties in others. Lack of a full appreciation of this variability may be at the origin of some discrepancies in published work dealing with the properties of cuprizone mouse liver mitochondria (CMLM). 2 CMLM from fully affected livers were remarkably labile and difficult to isolate in a coupled state by homogenization and centrifugation techniques. The integral respiratory chain proteins of CMLM were functionally normal, with the exception of succinic dehydrogenase which showed considerable inhibition. Coupled morphological and functional analysis provided evidence that these properties were independent of CMLM size, a matter which had remained doubtful thus far and bears on the validity of literature reports.

Recently, we showed that generation of tumours in syngeneic mice by cells devoid of mitochondrial (mt) DNA (ρ0 cells) is linked to the acquisition of the host mtDNA. However, the mechanism of mtDNA movement between cells remains unresolved. To determine whether the transfer of mtDNA involves whole mitochondria, we injected B16ρ0 mouse melanoma cells into syngeneic C57BL/6Nsu9-DsRed2 mice that express red fluorescent protein in their mitochondria. We document that mtDNA is acquired by transfer of whole mitochondria from the host animal, leading to normalisation of mitochondrial respiration. Additionally, knockdown of key mitochondrial complex I (NDUFV1) and complex II (SDHC) subunits by shRNA in B16ρ0 cells abolished or significantly retarded their ability to form tumours. Collectively, these results show that intact mitochondria with their mtDNA payload are transferred in the developing tumour, and provide functional evidence for an essential role of oxidative phosphorylation in can...

High Altitude pulmonary edema (HApe) is a threatening disorder caused due to acute exposure to high altitude above 3000 m. Apart from multiple factors involved, the genetic factors also play an important function in the pathogenesis of HApe. this study aims to evaluate the role of mtDnA polymorphism and their association with haplogroup in understanding the etiology of HAPE. In this study, all the HAPE susceptible and acclimatized control subjects could be classified into nine haplogroups pertaining mostly to Macrohaplogroup M and U. The frequency of haplogroup M was significantly higher in HAPE susceptibles whereas the haplogroup M33a2′3 was found only in HAPE susceptibles. The variant G4491A and A4944G of MT-ND2, A14002G of MT-ND5, and C8562T of MT-ATP8, were definition site of haplogroup M33a2′3. The frequency of A10398G of MT-ND3, A8701G of MT-ATP6 and C14766T of MT-CYB genes were significantly higher in HAPE susceptibles. mtDNA copy number also plays a significant synergistic role in HAPE susceptibility. Our findings suggests that variants in MT-ND2 and MT-ND5 were predicted to confer decreased protein stability in HApe susceptibles and in particular, highly conserved variants G4491A, A4944G and A14002G associated with haplogroup M33a2′3 may be the primary cause of susceptibility to HAPE in Indian male lowlanders. Mitochondria are semiautonomous cytoplasmic organelles of the eukaryotic system that imparts essential functions in energy metabolism, free radical production, calcium homeostasis and apoptosis 1-3. In humans, mitochondrial DNA (mtDNA) is the extranuclear circular molecule that spans 16,569 bp and encodes genes of 13 proteins, 2 rRNAs and 22 tRNAs, as well as 121 bp regulatory region (the D-Loop), all of which are components of the electron transport chain (ETC), and are essential for oxidative phosphorylation (OXPHOS) 4. The OXPHOS system has a mixed genetic origin, nuclear and mitochondrial. It consists of approximately 90 different structural protein subunits of which thirteen are encoded by the mtDNA in humans 5. The mitochondrial genome encode seven subunits of complex I, one subunit of complex III, three subunits of complex IV and two subunits of complex V 6. High altitude Pulmonary Edema (HAPE) is a life threatening, multifactorial complex disease condition which occurs due to rapid ascent to high altitude ̴ 3000 m above sea level, where the oxygen content in air is only 60% of that at sea level 7. Genetic predisposition to the disease is largely unknown, but it would be a function of gene environment interaction 8. The role of genetics in determining the individual's susceptibility to HAPE is unclear. Variants of some genes CYP11B2, ACE, EDN1(nuclear genes) were previously investigated for their association with HAPE 9. The pathophysiology of HAPE is attributed to several etiological factors like pulmonary

Epithelial-to-mesenchymal transition (EMT) allows epithelial cancer cells to assume mesenchymal features, endowing them with enhanced motility and invasiveness, thus enabling cancer dissemination and metastatic spread. The induction of EMT is orchestrated by EMT-inducing transcription factors that switch on the expression of "mesenchymal" genes and switch off the expression of "epithelial" genes. Mitochondrial dysfunction is a hallmark of cancer and has been associated with progression to a metastatic and drug-resistant phenotype. The mechanistic link between metastasis and mitochondrial dysfunction is gradually emerging. The discovery that mitochondrial dysfunction owing to deregulated mitophagy, depletion of the mitochondrial genome (mitochondrial DNA) or mutations in Krebs' cycle enzymes, such as succinate dehydrogenase, fumarate hydratase, and isocitrate dehydrogenase, activate the EMT gene signature has provided evidence that mitochondrial dysfunction an...

Nutritional status, in particular overweight and obesity, as well as sedentarism and high-fat diet consumption, are important risk factors to develop chronic diseases, which have a higher impact on the elderly’s health. Therefore, these nutritional problems have become a concern to human healthspan and longevity. The fatty acids obtained thru the diet or due to fatty acid synthesis during obesity accumulate within the body generating toxicity and cell death. Fat is not only stored in adipose tissue, but it can also be stored in skeletal muscle. Palmitic acid (PA) has been reported as one of the most important saturated free fatty acids; it is associated to chronic oxidative stress and increased mitochondrial ROS production causing cell death by apoptosis. In skeletal muscle, palmitate has been associated with various pathophysiological consequences, which lead to muscle deterioration during aging and obesity. Since molecules that modify redox state have been proven to prevent cellul...

Thermodynamic analysis of spermine binding to mitochondria treated with ruthenium red and deenergized with either FCCP or antimycin A confirms the presence of two polyamine binding sites, S I and S P , both with monocoordination, as previously observed in energized mitochondria [Dalla Via et al., Biochim. Biophys. Acta 1284 (1996) 247^252]. Both sites undergo a marked change in binding capacity and binding affinity upon mitochondrial deenergization. This change is most likely responsible for the incomplete or delayed sperminemediated inhibition of the permeability transition induced in deenergized mitochondria.

Although mitochondrial dysfunction plays a key role in the pathophysiology of acute kidney injury (AKI), the influence of mitochondrial genetic variability in this process remains unclear. We explored the association between the risk of post-cardiac bypass AKI and mitochondrial haplotype-inherited mitochondrial genomic variations of potentially functional significance. Our single-centre study recruited consecutive patients prior to surgery. Exclusions included stage 5 CKD, non-Caucasian race and subsequent off-pump surgery. Haplogroup analysis allowed characterisation of the study population using the common mutations and by phylogenetic supergroup (WXI and HV). Chi-square tests for association allowed the identification of potential predictors of AKI for use in logistic regression analysis. AKI occurred in 12.8% of the study population (n = 881; male 69.6%, non-diabetic 78.5%, median (interquartile range) age 68.0 (61.0-75.0) years). The haplogroup profile comprised H (42.7%), J (12.1%), T (10.9%), U (14.4%) and K (7.6%). Although the regression model was statistically significant (χ 2 = 95.483, p < 0.0005), neither the phylogenetic supergroups nor any individual haplogroup was a significant contributor. We found no significant association between common European haplogroups and the risk of post-cardiac bypass AKI. However, given the major role of mitochondrial dysfunction in AKI, there is a need to replicate our findings in other cohorts and with other aetiologies of AKI. Acute kidney injury (AKI) is a common adverse outcome of cardiac surgery and affects around 18% of patients 1. The incidence of more severe AKI, requiring renal support, has been reported at 1-2% across various series 2-5 and is associated with mortality rates of at least 45% 2,4,5. The pathogenesis of the AKI occurring after cardio-pulmonary bypass may include ischaemia-reperfusion injury, inflammation induced in the extracorporeal blood circuit, haemolysis, embolization and medication-related injury 1. Disruption of cellular energetics appears to be a common pathway for many of these factors, as it is in all forms of ischaemic AKI 6 , with mitochondria playing a pivotal role in this process 7. Subtle differences in mitochondrial function may, therefore, affect susceptibility to AKI through their impact on cellular energy production, free radical generation and metabolic uncoupling. With this in mind, inherited variation in the mitochondrial genome has not only allowed human populations to be categorized into different mitochondrial haplogroups, but may also be of functional significance 8 ; associations have been found, for instance, between mitochondrial haplotype and Alzheimer's disease 9 , Parkinson's disease 10 and ischaemic stroke 11 , and with physiological functions such as sperm motility 12. Work undertaken within our group has also shown that haplogroup H-the commonest haplotype in European populations 12-was associated with improved survival after sepsis in comparison to non-haplogroup H subjects 13. This observation has physiological credibility as subjects with this haplotype have higher respiratory chain activity 12 and so may be less prone to the risks of the tissue dysoxia that occurs in sepsis 14. A relationship between mitochondrial genetic variability, mitochondrial function and susceptibility to AKI is, therefore, biologically plausible. Our study tested the hypothesis that the development of post-cardiopulmonary

Nutritional status, in particular overweight and obesity, as well as sedentarism and high-fat diet consumption, are important risk factors to develop chronic diseases, which have a higher impact on the elderly’s health. Therefore, these nutritional problems have become a concern to human healthspan and longevity. The fatty acids obtained thru the diet or due to fatty acid synthesis during obesity accumulate within the body generating toxicity and cell death. Fat is not only stored in adipose tissue, but it can also be stored in skeletal muscle. Palmitic acid (PA) has been reported as one of the most important saturated free fatty acids; it is associated to chronic oxidative stress and increased mitochondrial ROS production causing cell death by apoptosis. In skeletal muscle, palmitate has been associated with various pathophysiological consequences, which lead to muscle deterioration during aging and obesity. Since molecules that modify redox state have been proven to prevent cellul...

Epithelial-to-mesenchymal transition (EMT) allows epithelial cancer cells to assume mesenchymal features, endowing them with enhanced motility and invasiveness, thus enabling cancer dissemination and metastatic spread. The induction of EMT is orchestrated by EMT-inducing transcription factors that switch on the expression of &quot;mesenchymal&quot; genes and switch off the expression of &quot;epithelial&quot; genes. Mitochondrial dysfunction is a hallmark of cancer and has been associated with progression to a metastatic and drug-resistant phenotype. The mechanistic link between metastasis and mitochondrial dysfunction is gradually emerging. The discovery that mitochondrial dysfunction owing to deregulated mitophagy, depletion of the mitochondrial genome (mitochondrial DNA) or mutations in Krebs&#39; cycle enzymes, such as succinate dehydrogenase, fumarate hydratase, and isocitrate dehydrogenase, activate the EMT gene signature has provided evidence that mitochondrial dysfunction an...

High Altitude pulmonary edema (HApe) is a threatening disorder caused due to acute exposure to high altitude above 3000 m. Apart from multiple factors involved, the genetic factors also play an important function in the pathogenesis of HApe. this study aims to evaluate the role of mtDnA polymorphism and their association with haplogroup in understanding the etiology of HAPE. In this study, all the HAPE susceptible and acclimatized control subjects could be classified into nine haplogroups pertaining mostly to Macrohaplogroup M and U. The frequency of haplogroup M was significantly higher in HAPE susceptibles whereas the haplogroup M33a2′3 was found only in HAPE susceptibles. The variant G4491A and A4944G of MT-ND2, A14002G of MT-ND5, and C8562T of MT-ATP8, were definition site of haplogroup M33a2′3. The frequency of A10398G of MT-ND3, A8701G of MT-ATP6 and C14766T of MT-CYB genes were significantly higher in HAPE susceptibles. mtDNA copy number also plays a significant synergistic role in HAPE susceptibility. Our findings suggests that variants in MT-ND2 and MT-ND5 were predicted to confer decreased protein stability in HApe susceptibles and in particular, highly conserved variants G4491A, A4944G and A14002G associated with haplogroup M33a2′3 may be the primary cause of susceptibility to HAPE in Indian male lowlanders. Mitochondria are semiautonomous cytoplasmic organelles of the eukaryotic system that imparts essential functions in energy metabolism, free radical production, calcium homeostasis and apoptosis 1-3. In humans, mitochondrial DNA (mtDNA) is the extranuclear circular molecule that spans 16,569 bp and encodes genes of 13 proteins, 2 rRNAs and 22 tRNAs, as well as 121 bp regulatory region (the D-Loop), all of which are components of the electron transport chain (ETC), and are essential for oxidative phosphorylation (OXPHOS) 4. The OXPHOS system has a mixed genetic origin, nuclear and mitochondrial. It consists of approximately 90 different structural protein subunits of which thirteen are encoded by the mtDNA in humans 5. The mitochondrial genome encode seven subunits of complex I, one subunit of complex III, three subunits of complex IV and two subunits of complex V 6. High altitude Pulmonary Edema (HAPE) is a life threatening, multifactorial complex disease condition which occurs due to rapid ascent to high altitude ̴ 3000 m above sea level, where the oxygen content in air is only 60% of that at sea level 7. Genetic predisposition to the disease is largely unknown, but it would be a function of gene environment interaction 8. The role of genetics in determining the individual's susceptibility to HAPE is unclear. Variants of some genes CYP11B2, ACE, EDN1(nuclear genes) were previously investigated for their association with HAPE 9. The pathophysiology of HAPE is attributed to several etiological factors like pulmonary

F-ATP synthase is a leading candidate as the mitochondrial permeability transition pore (PTP) but the mechanism(s) leading to channel formation remain undefined. Here, to shed light on the structural requirements for PTP formation, we test cells ablated for g, OSCP and b subunits, and ρ0 cells lacking subunits a and A6L. Δg cells (that also lack subunit e) do not show PTP channel opening in intact cells or patch-clamped mitoplasts unless atractylate is added. Δb and ΔOSCP cells display currents insensitive to cyclosporin A but inhibited by bongkrekate, suggesting that the adenine nucleotide translocator (ANT) can contribute to channel formation in the absence of an assembled F-ATP synthase. Mitoplasts from ρ0 mitochondria display PTP currents indistinguishable from their wild-type counterparts. In this work, we show that peripheral stalk subunits are essential to turn the F-ATP synthase into the PTP and that the ANT provides mitochondria with a distinct permeability pathway.

Converting carcinomas in benign oncocytomas has been suggested as a potential anti-cancer strategy. One of the oncocytoma hallmarks is the lack of respiratory complex I (CI). Here we use genetic ablation of this enzyme to induce indolence in two cancer types, and show this is reversed by allowing the stabilization of Hypoxia Inducible Factor-1 alpha (HIF-1α). We further show that on the long run CI-deficient tumors re-adapt to their inability to respond to hypoxia, concordantly with the persistence of human oncocytomas. We demonstrate that CI-deficient tumors survive and carry out angiogenesis, despite their inability to stabilize HIF-1α. Such adaptive response is mediated by tumor associated macrophages, whose blockage improves the effect of CI ablation. Additionally, the simultaneous pharmacological inhibition of CI function through metformin and macrophage infiltration through PLX-3397 impairs tumor growth in vivo in a synergistic manner, setting the basis for an efficient combinatorial adjuvant therapy in clinical trials.

The generally accepted model of energy systems has been used for many years. When exercise intensity rises and glucose uptake by working muscles is increased, a drop in circulating glucose is observed while in higher intensity exercise, muscle glucose uptake can increase by as much as 30-50 times, compared to the resting rate. Changes is glucose metabolism have been described by numerous authors and forms an integral part of the modification of energy systems to training stimulus. This is integral to understanding the changes that may occur in the use of blood borne glucose and intra muscular glycogen that may be a marker of exercise intensity. Further Increased cytosolic and more effectively mitochondrial calcium during high ATP turnover in exercise increases glucose phosphorylation while in some cells MAS converted lactate to pyruvate whereas glucose oxidation and lactate production are influenced by the activity of MAS when the intensity of exercise rises, it can lead to down-regulation of MAS activity, which leads to an increase in lactate production Where MAS is inhibited, there is a 50% decrease in lactate oxidation. Likely sites for the adaptation of MAS are highlighted and the effect that this can have on our view of how the energy systems function during high intensity exercise are also suggested. Through consideration of these metabolic events a new vision of energy system function is proposed.

Neoplastic cells display reprogrammed metabolism due to the heightened energetic demands and the need for biomass synthesis of a growing tumor. Targeting metabolic vulnerabilities is thus an important goal for cancer therapy. Here, we describe a novel small-molecule arylsulfonamide (N-cyclobutyl-N-((2,2-dimethyl-2-pyrano[3,2-]pyridin-6-yl)methyl)-3,4-dimethoxybenzenesulfonamide) that exerts potent cytotoxicity and energetic stress on tumor cells while largely sparing non-cancerous human cells. In tumor cells, it stimulates glycolysis and accelerates glucose consumption. Consequently, intracellular ATP levels plummet, triggering activation of AMP-activated protein kinase (AMPK), and diminishing the mammalian target of rapamycin complex 1 (mTORC1) and hypoxia-inducible factor 1 (HIF-1) signaling. In orthotopic triple-negative breast cancer and subcutaneous lung cancer mouse models, this arylsulfonamide robustly suppresses primary tumor growth, inhibits the formation of distant metasta...

Since the initial description of astrocytes by neuroanatomists of the nineteenth century, a critical metabolic role for these cells has been suggested in the central nervous system. Nonetheless, it took several technological and conceptual advances over many years before we could start to understand how they fulfill such a role. One of the important and early recognized metabolic function of astrocytes concerns the reuptake and recycling of the neurotransmitter glutamate. But the description of this initial property will be followed by several others including an implication in the supply of energetic substrates to neurons. Indeed, despite the fact that like most eukaryotic non-proliferative cells, astrocytes rely on oxidative metabolism for energy production, they exhibit a prominent aerobic glycolysis capacity. Moreover, this unusual metabolic feature was found to be modulated by glutamatergic activity constituting the initial step of the neurometabolic coupling mechanism. Several...

Brain energetic requirements are elevated due to the high cost of impulse transmission and information storage, and are met mainly by glucose oxidation. The energy needs are closely matched by metabolic regulation, which requires the close cooperation of neurons and astrocytes and involves highly regulated fluxes of metabolites between cells. The metabolism in each type of cell is determined in part by its proteomic profile, which has been regarded as complementary. This review will consider the cellular distribution of the mitochondrial aspartate-glutamate carrier, aralar/AGC1/SLC25A12, and its role in the synergic metabolism between neurons and astrocytes.

Conclusions Microarray analysis identified expression differences between troponin-positive and troponin-negative patients over time. Specific biological pathways possibly showing the late effects of acute events can be used to discover biomarkers of coronary heart disease.

The glutamate-dependent respiration of isolated BM (brain mitochondria) is regulated by Ca2+cyt (cytosolic Ca2+) (S0.5=225±22 nM) through its effects on aralar. We now also demonstrate that the α-glycerophosphate-dependent respiration is controlled by Ca2+cyt (S0.5=60±10 nM). At higher Ca2+cyt (&gt;600 nM), BM accumulate Ca2+ which enhances the rate of intramitochondrial dehydrogenases. The Ca2+-induced increments of state 3 respiration decrease with substrate in the order glutamate&gt;α-oxoglutarate&gt;isocitrate&gt;α-glycerophosphate&gt;pyruvate. Whereas the oxidation of pyruvate is only slightly influenced by Ca2+cyt, we show that the formation of pyruvate is tightly controlled by Ca2+cyt. Through its common substrate couple NADH/NAD+, the formation of pyruvate by LDH (lactate dehydrogenase) is linked to the MAS (malate–aspartate shuttle) with aralar as a central component. A rise in Ca2+cyt in a reconstituted system consisting of BM, cytosolic enzymes of MAS and LDH causes an up...