scholarly journals Relieving Cellular Energy Stress in Aging, Neurodegenerative, and Metabolic Diseases, SIRT1 as a Therapeutic and Promising Node

2021 ◽  
Vol 13 ◽  
Author(s):  
Yang Fang ◽  
Xifeng Wang ◽  
Danying Yang ◽  
Yimei Lu ◽  
Gen Wei ◽  
...  
Keyword(s):  
Neurodegenerative Diseases ◽  
Metabolic Diseases ◽  
Energy State ◽  
Energy Status ◽  
Atp Production ◽  
Energy Stress ◽  
Silent Information Regulator 1 ◽  
The Stability ◽  
Intracellular Energy ◽  
Expression And Activity

The intracellular energy state will alter under the influence of physiological or pathological stimuli. In response to this change, cells usually mobilize various molecules and their mechanisms to promote the stability of the intracellular energy status. Mitochondria are the main source of ATP. Previous studies have found that the function of mitochondria is impaired in aging, neurodegenerative diseases, and metabolic diseases, and the damaged mitochondria bring lower ATP production, which further worsens the progression of the disease. Silent information regulator-1 (SIRT1) is a multipotent molecule that participates in the regulation of important biological processes in cells, including cellular metabolism, cell senescence, and inflammation. In this review, we mainly discuss that promoting the expression and activity of SIRT1 contributes to alleviating the energy stress produced by physiological and pathological conditions. The review also discusses the mechanism of precise regulation of SIRT1 expression and activity in various dimensions. Finally, according to the characteristics of this mechanism in promoting the recovery of mitochondrial function, the relationship between current pharmacological preparations and aging, neurodegenerative diseases, metabolic diseases, and other diseases was analyzed.

scholarly journals The Emerging Roles of the Calcineurin-Nuclear Factor of Activated T-Lymphocytes Pathway in Nervous System Functions and Diseases

2016 ◽  
Vol 2016 ◽  
pp. 1-20 ◽  
Author(s):  
Maulilio John Kipanyula ◽  
Wahabu Hamisi Kimaro ◽  
Paul F. Seke Etet
Keyword(s):  
Nervous System ◽  
T Lymphocytes ◽  
Neurodegenerative Diseases ◽  
Psychotic Disorders ◽  
Spinal Cord Injuries ◽  
Metabolic Diseases ◽  
Nuclear Factor ◽  
Activated T Lymphocytes ◽  
Endogenous Regulators ◽  
Brain And Spinal Cord

The ongoing epidemics of metabolic diseases and increase in the older population have increased the incidences of neurodegenerative diseases. Evidence from murine and cell line models has implicated calcineurin-nuclear factor of activated T-lymphocytes (NFAT) signaling pathway, a Ca2+/calmodulin-dependent major proinflammatory pathway, in the pathogenesis of these diseases. Neurotoxins such as amyloid-β, tau protein, andα-synuclein trigger abnormal calcineurin/NFAT signaling activities. Additionally increased activities of endogenous regulators of calcineurin like plasma membrane Ca2+-ATPase (PMCA) and regulator of calcineurin 1 (RCAN1) also cause neuronal and glial loss and related functional alterations, in neurodegenerative diseases, psychotic disorders, epilepsy, and traumatic brain and spinal cord injuries. Treatment with calcineurin/NFAT inhibitors induces some degree of neuroprotection and decreased reactive gliosis in the central and peripheral nervous system. In this paper, we summarize and discuss the current understanding of the roles of calcineurin/NFAT signaling in physiology and pathologies of the adult and developing nervous system, with an emphasis on recent reports and cutting-edge findings. Calcineurin/NFAT signaling is known for its critical roles in the developing and adult nervous system. Its role in physiological and pathological processes is still controversial. However, available data suggest that its beneficial and detrimental effects are context-dependent. In view of recent reports calcineurin/NFAT signaling is likely to serve as a potential therapeutic target for neurodegenerative diseases and conditions. This review further highlights the need to characterize better all factors determining the outcome of calcineurin/NFAT signaling in diseases and the downstream targets mediating the beneficial and detrimental effects.

scholarly journals PPARs in Liver Diseases and Cancer: Epigenetic Regulation by MicroRNAs

PPAR Research ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-16 ◽  
Author(s):  
Marion Peyrou ◽  
Pierluigi Ramadori ◽  
Lucie Bourgoin ◽  
Michelangelo Foti
Keyword(s):  
Liver Diseases ◽  
Metabolic Diseases ◽  
Viral Infections ◽  
Inflammatory Responses ◽  
Current Knowledge ◽  
Hepatocellular Adenoma ◽  
Peroxisome Proliferator ◽  
Cancer Therapies ◽  
Ppar Agonists ◽  
Expression And Activity

Peroxisome-proliferator-activated receptors (PPARs) are ligand-activated nuclear receptors that exert in the liver a transcriptional activity regulating a whole spectrum of physiological functions, including cholesterol and bile acid homeostasis, lipid/glucose metabolism, inflammatory responses, regenerative mechanisms, and cell differentiation/proliferation. Dysregulations of the expression, or activity, of specific PPAR isoforms in the liver are therefore believed to represent critical mechanisms contributing to the development of hepatic metabolic diseases, disorders induced by hepatic viral infections, and hepatocellular adenoma and carcinoma. In this regard, specific PPAR agonists have proven to be useful to treat these metabolic diseases, but for cancer therapies, the use of PPAR agonists is still debated. Interestingly, in addition to previously described mechanisms regulating PPARs expression and activity, microRNAs are emerging as new important regulators of PPAR expression and activity in pathophysiological conditions and therefore may represent future therapeutic targets to treat hepatic metabolic disorders and cancers. Here, we reviewed the current knowledge about the general roles of the different PPAR isoforms in common chronic metabolic and infectious liver diseases, as well as in the development of hepatic cancers. Recent works highlighting the regulation of PPARs by microRNAs in both physiological and pathological situations with a focus on the liver are also discussed.

Simple Leg Placement Strategy for a One Legged Running Model

2012 ◽  
Author(s):  
Timothy Sullivan ◽  
Justin Seipel
Keyword(s):  
Stance Phase ◽  
Energy State ◽  
Center Of Mass ◽  
Mass Movement ◽  
Legged Locomotion ◽  
Energy Conserving ◽  
Lower Torque ◽  
The Stability ◽  
Time Required ◽  
Torque Values

The Spring Loaded Inverted Pendulum (SLIP) model was developed to describe center of mass movement patterns observed in animals, using only a springy leg and a point mass. However, SLIP is energy conserving and does not accurately represent any biological or robotic system. Still, this model is often used as a foundation for the investigation of improved legged locomotion models. One such model called Torque Damped SLIP (TD-SLIP) utilizes two additional parameters, a time dependent torque and dampening to drastically increase the stability. Forced Damped SLIP (FD-SLIP), a predecessor of TD-SLIP, has shown that this model can be further simplified by using a constant torque, instead of a time varying torque, while still maintaining stability. Using FD-SLIP as a base, this paper explores a leg placement strategy using a simple PI controller. The controller takes advantage of the fact that the energy state of FD-SLIP is symmetric entering and leaving the stance phase during steady state conditions. During the flight phase, the touch down leg angle is adjusted so that the energy dissipation due to dampening, during the stance phase, compensates for any imbalance of energy. This controller approximately doubles the region of stability when subjected to velocity perturbations at touchdown, enables the model to operate at considerably lower torque values, and drastically reduces the time required to recover from a perturbation, while using less energy. Finally, the leg placement strategy used effectively imitates the natural human response to velocity perturbations while running.

scholarly journals Mitochondria surveillance systems trigger innate immune responses to bacterial pathogens via AMPK pathway in C. elegans

2020 ◽  
Author(s):  
Shouyong Ju ◽  
Hanqiao Chen ◽  
Shaoying Wang ◽  
Jian Lin ◽  
Raffi V Aroian ◽  
...  
Keyword(s):  
Immune System ◽  
Immune Responses ◽  
Innate Immune ◽  
Surveillance Systems ◽  
Innate Immune Responses ◽  
Energy Status ◽  
Microbial Infection ◽  
C Elegans ◽  
Host Interaction ◽  
Intracellular Energy

AbstractPathogen recognition and triggering pattern of host innate immune system is critical to understanding pathogen-host interaction. It is generally accepted that the microbial infection can be recognized by host via pattern-triggered immunity (PTI) or effector-triggered immunity (ETI) responses. Recently, non-PRR-mediated cellular surveillance systems have been reported as an important supplement strategy to PTI and ETI responses. However, the mechanism of how surveillance systems sense pathogens and trigger innate immune responses is largely unknown. In the present study, using Bacillus thuringiensis-Caenorhabditis elegans as a model, we found a new approach for surveillance systems to sense the pathogens through no-PPRs patterns. We reported C. elegans can monitor intracellular energy status through the mitochondrial surveillance system to triggered innate immune responses against pathogenic attack via AMP-activated protein kinase (AMPK). Consider that the mitochondria surveillance systems and AMPK are conserved components from worms to mammals, our study suggests that disrupting mitochondrial homeostasis to activate the immune system through AMPK-dependent pathways may widely existing in animals.

scholarly journals CARDIOKIN1: Computational Assessment of Myocardial Metabolic Capability in Healthy Controls and Patients With Valve Diseases

Circulation ◽  
2021 ◽  
Author(s):  
Nikolaus Berndt ◽  
Johannes Eckstein ◽  
Iwona Wallach ◽  
Sarah Nordmeyer ◽  
Marcus Kelm ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Energy Demand ◽  
Heart Diseases ◽  
Cardiac Metabolism ◽  
Production Reserve ◽  
Energy Status ◽  
Tissue Samples ◽  
Atp Production ◽  
Mechanic Energy

Background: Many heart diseases can develop a reduced pumping capacity of the heart muscle. A mismatch between ATP demand and ATP production of cardiomyocytes is one of the possible causes. Assessment of the relation between the myocardial ATP production (MV ATP ) and cardiac workload is important for better understanding disease development and choice of nutritional or pharmacological treatment strategies. As there is currently no method for the measurement of MV ATP in vivo , the use of physiology-based metabolic models in conjunction with protein abundance data is an attractive approach. Methods: We developed a comprehensive kinetic model of the cardiac energy metabolism (CARDIOKIN1), which recapitulates numerous experimental findings on cardiac metabolism obtained with isolated cardiomyocytes, perfused animal hearts and in vivo studies with humans. We used the model to assess the energy status of the left ventricle (LV) of healthy subjects and patients with aortic stenosis (AS) and mitral valve insufficiency (MI). Maximal enzyme activities were individually scaled by means of protein abundances in LV tissue samples. The energy status of the LV was quantified by the ATP consumption at rest (MV ATP (rest)), at maximal workload (MV ATP (max)), and by the myocardial ATP production reserve (MAPR) representing the span between MV ATP (rest) and MV ATP (max). Results: Compared with controls, in both groups of patients, MV ATP (rest) was increased and MV ATP (max) was decreased resulting in a decreased MAPR, although all patients had preserved ejection fraction. Notably, the variance of the energetic status was high ranging from decreased to normal values. In both patient groups, the energetic status was tightly associated with mechanic energy demand. Moreover, a decrease of MV ATP (max) was associated with a decrease of the cardiac output indicating that cardiac functionality and energetic performance of the ventricle are closely coupled. Conclusions: Our analysis suggests that the ATP producing capacity of the LV of patients with valvular dysfunction is generally diminished and correlates positively with mechanic energy demand and cardiac output. However, large differences exist in the energetic state of the myocardium even in patients with similar clinical or image-based markers of hypertrophy and pump function.

scholarly journals Kinetic Modeling of the Mitochondrial Energy Metabolism of Neuronal Cells: The Impact of Reducedα-Ketoglutarate Dehydrogenase Activities on ATP Production and Generation of Reactive Oxygen Species

2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Nikolaus Berndt ◽  
Sascha Bulik ◽  
Hermann-Georg Holzhütter
Keyword(s):  
Reactive Oxygen Species ◽  
Neurodegenerative Diseases ◽  
Neuronal Cells ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Mitochondrial Energy Metabolism ◽  
Atp Production ◽  
Dependent Inactivation ◽  
The Impact ◽  
Ketoglutarate Dehydrogenase

Reduced activity of brain α-ketoglutarate dehydrogenase complex (KGDHC) occurs in a number of neurodegenerative diseases like Parkinson's disease and Alzheimer's disease. In order to quantify the relation between diminished KGDHC activity and the mitochondrial ATP generation, redox state, transmembrane potential, and generation of reactive oxygen species (ROS) by the respiratory chain (RC), we developed a detailed kinetic model. Model simulations revealed a threshold-like decline of the ATP production rate at about 60% inhibition of KGDHC accompanied by a significant increase of the mitochondrial membrane potential. By contrast, progressive inhibition of the enzyme aconitase had only little impact on these mitochondrial parameters. As KGDHC is susceptible to ROS-dependent inactivation, we also investigated the reduction state of those sites of the RC proposed to be involved in ROS production. The reduction state of all sites except one decreased with increasing degree of KGDHC inhibition suggesting an ROS-reducing effect of KGDHC inhibition. Our model underpins the important role of reduced KGDHC activity in the energetic breakdown of neuronal cells during development of neurodegenerative diseases.

scholarly journals Update on FXR Biology: Promising Therapeutic Target?

2018 ◽  
Vol 19 (7) ◽  
pp. 2069 ◽  
Author(s):  
Chang Han
Keyword(s):  
Therapeutic Target ◽  
Energy Homeostasis ◽  
Metabolic Diseases ◽  
Current Knowledge ◽  
Farnesoid X Receptor ◽  
Metabolic Effects ◽  
Metabolic Dysfunction ◽  
Energy Status ◽  
Safety Issues ◽  
Attractive Therapeutic Target

Farnesoid X receptor (FXR), a metabolic nuclear receptor, plays critical roles in the maintenance of systemic energy homeostasis and the integrity of many organs, including liver and intestine. It regulates bile acid, lipid, and glucose metabolism, and contributes to inter-organ communication, in particular the enterohepatic signaling pathway, through bile acids and fibroblast growth factor-15/19 (FGF-15/19). The metabolic effects of FXR are also involved in gut microbiota. In addition, FXR has various functions in the kidney, adipose tissue, pancreas, cardiovascular system, and tumorigenesis. Consequently, the deregulation of FXR may lead to abnormalities of specific organs and metabolic dysfunction, allowing the protein as an attractive therapeutic target for the management of liver and/or metabolic diseases. Indeed, many FXR agonists have been being developed and are under pre-clinical and clinical investigations. Although obeticholic acid (OCA) is one of the promising candidates, significant safety issues have remained. The effects of FXR modulation might be multifaceted according to tissue specificity, disease type, and/or energy status, suggesting the careful use of FXR agonists. This review summarizes the current knowledge of systemic FXR biology in various organs and the gut–liver axis, particularly regarding the recent advancement in these fields, and also provides pharmacological aspects of FXR modulation for rational therapeutic strategies and novel drug development.

scholarly journals Adenosine and ATP-sensitive potassium channels modulate dopamine release in the anoxic turtle (Trachemys scripta) striatum

2005 ◽  
Vol 289 (1) ◽  
pp. R77-R83 ◽  
Author(s):  
Sarah L. Milton ◽  
Peter L. Lutz
Keyword(s):  
Dopamine Release ◽  
Trachemys Scripta ◽  
Mammalian Brain ◽  
Freshwater Turtle ◽  
Energy Status ◽  
Gbr 12909 ◽  
Butanedione Monoxime ◽  
Intracellular Energy

Excessive dopamine (DA) is known to cause hypoxic/ischemic damage to mammalian brain. The freshwater turtle Trachemys scripta, however, maintains basal striatal DA levels in anoxia. We investigated DA balance during early anoxia when energy status in the turtle brain is compromised. The roles of ATP-sensitive potassium (KATP) channels and adenosine (AD) receptors were investigated as these factors affect DA balance in mammalian neurons. Striatal extracellular DA was determined by microdialysis with HPLC in the presence or absence of the specific DA transport blocker GBR-12909, the KATP blocker 2,3-butanedione monoxime, or the nonspecific AD receptor blocker theophylline. We found that in contrast to long-term anoxia, blocking DA reuptake did not significantly increase extracellular levels in 1-h anoxic turtles. Low DA levels in early anoxia were maintained instead by activation of KATP channels and AD receptors. Blocking KATP resulted in a 227% increase in extracellular DA in 1-h anoxic turtles but had no effect after 4 h of anoxia. Similarly, blocking AD receptors increased DA during the first hour of anoxia but did not change DA levels at 4-h anoxia. Support for the role of KATP channels in DA balance comes from normoxic animals treated with KATP opener; infusing diazoxide but not adenosine into the normoxic turtle striatum resulted in an immediate DA decrease to 14% of basal values within 1.5 h. Alternative strategies to maintain low extracellular levels may prevent catastrophic DA increases when intracellular energy is compromised while permitting the turtle to maintain a functional neuronal network during long-term anoxia.

scholarly journals Sustained ER stress promotes hyperglycemia by increasing glucagon action through the deubiquitinating enzyme USP14

2019 ◽  
Vol 116 (43) ◽  
pp. 21732-21738 ◽  
Author(s):  
Bin Liu ◽  
Zhijian Zhang ◽  
Yanyun Hu ◽  
Yan Lu ◽  
Duanzhuo Li ◽  
...  
Keyword(s):  
Er Stress ◽  
Metabolic Diseases ◽  
Low Grade ◽  
Deubiquitinating Enzyme ◽  
Obese Mice ◽  
Hepatic Gluconeogenesis ◽  
Regulatory Pathways ◽  
Underlying Mechanisms ◽  
The Stability ◽  
Glucose Output

Endoplasmic reticulum (ER) stress plays an important role in metabolic diseases like obesity and type 2 diabetes mellitus (T2DM), although the underlying mechanisms and regulatory pathways remain to be elucidated. Here, we induced chronic low-grade ER stress in lean mice to levels similar to those in high-fat diet (HFD)–fed obese mice and found that it promoted hyperglycemia due to enhanced hepatic gluconeogenesis. Mechanistically, sustained ER stress up-regulated the deubiquitinating enzyme ubiquitin-specific peptidase 14 (USP14), which increased the stability and levels of 3′,5′-cyclic monophosphate–responsive element binding (CREB) protein (CBP) to enhance glucagon action and hepatic gluconeogenesis. Exogenous overexpression of USP14 in the liver significantly increased hepatic glucose output. Consistent with this, liver-specific knockdown of USP14 abrogated the effects of ER stress on glucose metabolism, and also improved hyperglycemia and glucose intolerance in obese mice. In conclusion, our findings show a mechanism underlying ER stress-induced disruption of glucose homeostasis, and present USP14 as a potential therapeutic target against T2DM.

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