A Novel MAO-B/SSAO Inhibitor Improves Multiple Aspects of Dystrophic Phenotype in Mice.

Duchenne muscular dystrophy (DMD) is one of the most frequent and severe childhood muscle diseases. Its pathophysiology is multifaceted and still incompletely understood, but we and others have previously shown that oxidative stress plays an important role. In particular, we have demonstrated that inhibition of mitochondrial monoamine oxidases could improve some functional and biohumoral markers of the pathology.

Oxidative Stress by the Mitochondrial Monoamine Oxidase B Mediates Calcium Pyrophosphate Crystal-Induced Arthritis.

Objective: Calcium pyrophosphate (CPP) crystal deposition in the joints is associated with a heterogeneous set of debilitating syndromes characterized by inflammation and pain, for which no effective therapies are currently available. Because we found that the mitochondrial enzyme monoamine oxidase B (MAO-B) plays a fundamental role in promoting inflammatory pathways, this study aims at assessing the efficacy of two clinical-grade inhibitors (iMAO-Bs) in preclinical models of this disease to pave the way for a novel treatment.

Methods: We tested our hypothesis in two murine models of CPP-induced arthritis, by measuring cytokine and chemokine levels, along with immune cell recruitment.

OPA1 drives macrophage metabolism and functional commitment via p65 signaling.

Macrophages are essential players for the host response against pathogens, regulation of inflammation and tissue regeneration. The wide range of macrophage functions rely on their heterogeneity and plasticity that enable a dynamic adaptation of their responses according to the surrounding environmental cues. Recent studies suggest that metabolism provides synergistic support for macrophage activation and elicitation of desirable immune responses; however, the metabolic pathways orchestrating macrophage activation are still under scrutiny.

3D in vitro Models of Pathological Skeletal Muscle: Which Cells and Scaffolds to Elect?

Skeletal muscle is a fundamental tissue of the human body with great plasticity and adaptation to diseases and injuries. Recreating this tissue helps not only to deepen its functionality, but also to simulate pathophysiological processes. In this review we discuss the generation of human skeletal muscle three-dimensional (3D) models obtained through tissue engineering approaches.

The J2-Immortalized Murine Macrophage Cell Line Displays Phenotypical and Metabolic Features of Primary BMDMs in Their M1 and M2 Polarization State.

Macrophages are immune cells that are important for the development of the defensive front line of the innate immune system. Following signal recognition, macrophages undergo activation toward specific functional states, consisting not only in the acquisition of specific features but also of peculiar metabolic programs associated with each function. For these reasons, macrophages are often isolated from mice to perform cellular assays to study the mechanisms mediating immune cell activation.

Reactive Oxygen Species in Macrophages: Sources and Targets.

Reactive oxygen species (ROS) are fundamental for macrophages to eliminate invasive microorganisms. However, as observed in nonphagocytic cells, ROS play essential roles in processes that are different from pathogen killing, as signal transduction, differentiation, and gene expression. The different outcomes of these events are likely to depend on the specific subcellular site of ROS formation, as well as the duration and extent of ROS production.

N-acetylaspartate release by glutaminolytic ovarian cancer cells sustains protumoral macrophages.

Glutaminolysis is known to correlate with ovarian cancer aggressiveness and invasion. However, how this affects the tumor microenvironment is elusive. Here, we show that ovarian cancer cells become addicted to extracellular glutamine when silenced for glutamine synthetase (GS), similar to naturally occurring GS-low, glutaminolysis-high ovarian cancer cells.

Pharmacological targets of metabolism in disease: Opportunities from macrophages.

From advances in the knowledge of the immune system, it is emerging that the specialized functions displayed by macrophages during the course of an immune response are supported by specific and dynamically-connected metabolic programs. The study of immunometabolism is demonstrating that metabolic adaptations play a critical role in modulating inflammation and, conversely, inflammation deeply influences the acquisition of specific metabolic settings.This strict connection has been proven to be crucial for the execution of defined immune functional programs and it is now under investigation with respect to several human disorders, such as diabetes, sepsis, cancer, and autoimmunity.

Teaching an Old Molecule New Tricks: Drug Repositioning for Duchenne Muscular Dystrophy.

Duchenne muscular dystrophy (DMD) is one of the most severe forms of inherited muscular dystrophies. The disease is caused by the lack of dystrophin, a structurally essential protein; hence, a definitive cure would necessarily have to pass through some form of gene and/or cell therapy. Cell- and genetic-based therapeutics for DMD have been explored since the 1990s and recently, two of the latter have been approved for clinical use, but their efficacy is still very low.

Vanillic Acid Restores Coenzyme Q Biosynthesis and ATP Production in Human Cells Lacking .

Coenzyme Q (CoQ), a redox-active lipid, is comprised of a quinone group and a polyisoprenoid tail. It is an electron carrier in the mitochondrial respiratory chain, a cofactor of other mitochondrial dehydrogenases, and an essential antioxidant. CoQ requires a large set of enzymes for its biosynthesis; mutations in genes encoding these proteins cause primary CoQ deficiency, a clinically and genetically heterogeneous group of diseases.

Drug Repurposing for Duchenne Muscular Dystrophy: The Monoamine Oxidase B Inhibitor Safinamide Ameliorates the Pathological Phenotype in Mice and in Myogenic Cultures From DMD Patients.

Oxidative stress and mitochondrial dysfunction play a crucial role in the pathophysiology of muscular dystrophies. We previously reported that the mitochondrial enzyme monoamine oxidase (MAO) is a relevant source of reactive oxygen species (ROS) not only in murine models of muscular dystrophy, in which it directly contributes to contractile impairment, but also in muscle cells from collagen VI-deficient patients. Here, we now assessed the efficacy of a novel MAO-B inhibitor, safinamide, using and models of Duchenne muscular dystrophy (DMD).

Monoamine oxidase-dependent histamine catabolism accounts for post-ischemic cardiac redox imbalance and injury.

Monoamine oxidase (MAO), a mitochondrial enzyme that oxidizes biogenic amines generating hydrogen peroxide, is a major source of oxidative stress in cardiac injury. However, the molecular mechanisms underlying its overactivation in pathological conditions are still poorly characterized. Here, we investigated whether the enhanced MAO-dependent hydrogen peroxide production can be due to increased substrate availability using a metabolomic profiling method.

Live Cell Imaging in Microfluidic Device Proves Resistance to Oxygen/Glucose Deprivation in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes.

Analyses of cellular responses to fast oxygen dynamics are challenging and require ad hoc technological solutions, especially when decoupling from liquid media composition is required. In this work, we present a microfluidic device specifically designed for culture analyses with high resolution and magnification objectives, providing full optical access to the cell culture chamber. This feature allows fluorescence-based assays, photoactivated surface chemistry, and live cell imaging under tightly controlled pO environments.

Preliminary studies of berberine and its semi-synthetic derivatives as a promising class of multi-target anti-parkinson agents.

Parkinson's disease (PD) is a neurodegenerative disorder bearing motor and nonmotor symptoms. The treatment today is symptomatical rather than preventive or curative and this leaves the field open for the search of both novel molecular targets and drug candidates. Interference with α-synuclein fibrillation, monoamine oxidase (MAO) inhibition, modulation of adenosine receptors and the inhibition of specific phosphodiesterase (PDE) isoforms are some of the currently pursued strategies.

Piperine's mitigation of obesity and diabetes can be explained by its up-regulation of the metabolic rate of resting muscle.

We identify a target for treating obesity and type 2 diabetes, the consumption of calories by an increase in the metabolic rate of resting skeletal muscle. The metabolic rate of skeletal muscle can be increased by shifting myosin heads from the super-relaxed state (SRX), with a low ATPase activity, to a disordered relaxed state (DRX), with a higher ATPase activity. The shift of myosin heads was detected by a change in fluorescent intensity of a probe attached to the myosin regulatory light chain in skinned skeletal fibers, allowing us to perform a high-throughput screen of 2,128 compounds.

Spectroscopic Studies of the Super Relaxed State of Skeletal Muscle.

In the super-relaxed state of myosin, ATPase activity is strongly inhibited by binding of the myosin heads to the core of the thick filament in a structure known as the interacting-heads motif. In the disordered relaxed state myosin heads are not bound to the core of the thick filament and have an ATPase rate that is 10 fold greater. In the interacting-heads motif the two regulatory light chains appear to bind to each other.

Oxidative stress in muscular dystrophy: from generic evidence to specific sources and targets.

Muscular dystrophies (MDs) are a heterogeneous group of diseases that share a common end-point represented by muscular wasting. MDs are caused by mutations in a variety of genes encoding for different molecules, including extracellular matrix, transmembrane and membrane-associated proteins, cytoplasmic enzymes and nuclear proteins. However, it is still to be elucidated how genetic mutations can affect the molecular mechanisms underlying the contractile impairment occurring in these complex pathologies.

Oxidation of myofibrillar proteins in human heart failure.

Objectives: We investigated the incidence and contribution of the oxidation/nitrosylation of tropomyosin and actin to the contractile impairment and cardiomyocyte injury occurring in human end-stage heart failure (HF) as compared with nonfailing donor hearts.

Background: Although there is growing evidence that augmented intracellular accumulation of reactive oxygen/nitrogen species may play a key role in causing contractile dysfunction, there is a dearth of data regarding their contractile protein targets in human HF.

Methods: In left ventricular (LV) biopsies from explanted failing hearts (New York Heart Association functional class IV; HF group) and nonfailing donor hearts (NF group), carbonylation of actin and tropomyosin, disulphide cross-bridge (DCB) formation, and S-nitrosylation in tropomyosin were assessed, along with plasma troponin I and LV ejection fraction (LVEF).

α-Lactalbumin forms with oleic acid a high molecular weight complex displaying cytotoxic activity.

α-Lactalbumin (LA) forms with oleic acid (OA) a complex which has been reported to induce the selective death of tumor cells. However, the mechanism by which this complex kills a wide range of tumor cell lines is as yet largely unknown. The difficulty in rationalizing the cytotoxic effects of the LA/OA complex can be due to the fact that the molecular aspects of the interaction between the protein and the fatty acid are still poorly understood, in particular regarding the oligomeric state of the protein and the actual molar ratio of OA over protein in the complex.

Oxidative stress by monoamine oxidases is causally involved in myofiber damage in muscular dystrophy.

Several studies documented the key role of oxidative stress and abnormal production of reactive oxygen species (ROS) in the pathophysiology of muscular dystrophies (MDs). The sources of ROS, however, are still controversial as well as their major molecular targets. This study investigated whether ROS produced in mitochondria by monoamine oxidase (MAO) contributes to MD pathogenesis.

Mitochondrial injury and protection in ischemic pre- and postconditioning.

Mitochondrial damage is a determining factor in causing loss of cardiomyocyte function and viability, yet a mild degree of mitochondrial dysfunction appears to underlie cardioprotection against injury caused by postischemic reperfusion. This review is focused on two major mechanisms of mitochondrial dysfunction, namely, oxidative stress and opening of the mitochondrial permeability transition pore. The formation of reactive oxygen species in mitochondria will be analyzed with regard to factors controlling mitochondrial permeability transition pore opening.

Increased inducible nitric oxide synthase and arginase II expression in heart failure: no net nitrite/nitrate production and protein S-nitrosylation.

Our objective was to address the balance of inducible nitric oxide (NO) synthase (iNOS) and arginase and their contribution to contractile dysfunction in heart failure (HF). Excessive NO formation is thought to contribute to contractile dysfunction; in macrophages, increased iNOS expression is associated with increased arginase expression, which competes with iNOS for arginine. With substrate limitation, iNOS may become uncoupled and produce reactive oxygen species (ROS).

The oleic acid complexes of proteolytic fragments of alpha-lactalbumin display apoptotic activity.

The complexes formed by partially folded human and bovine alpha-lactalbumin with oleic acid (OA) have been reported to display selective apoptotic activity against tumor cells. These complexes were named human (HAMLET) or bovine (BAMLET) alpha-lactalbumin made lethal to tumor cells. Here, we analyzed the OA complexes formed by fragments of bovine alpha-lactalbumin obtained by limited proteolysis of the protein.

Mitochondria and cardioprotection.

Major factors linking mitochondrial dysfunction with myocardial injury are analyzed along with protective mechanisms elicited by endogenous processes and pharmacological treatments. In particular, a reduced rate of ATP hydrolysis and a slight increase in ROS formation appear to represent the prevailing components of self-defense mechanisms, especially in the case of ischemic preconditioning. These protective processes are activated by signaling pathways, which converge on mitochondria activating the mitochondrial K(ATP) channels and/or inhibiting the mitochondrial permeability transition pore.