Inhibiting Lysyl Oxidases prevents pathologic cartilage calcification.

Lysyl oxidases (LOX(L)) are enzymes that catalyze the formation of cross-links in collagen and elastin fibers during physiologic calcification of bone. However, it remains unknown whether they may promote pathologic calcification of articular cartilage, an important hallmark of debilitating arthropathies. Here, we have studied the possible roles of LOX(L) in cartilage calcification, related and not related to their cross-linking activity. We first demonstrated that inhibition of LOX(L) by ß-aminoproprionitrile (BAPN) significantly reduced calcification in murine and human chondrocytes, and in joint of meniscectomized mice. These BAPN's effects on calcification were accounted for by different LOX(L) roles. Firstly, reduced LOX(L)-mediated extracellular matrix cross-links downregulated Anx5, Pit1 and Pit2 calcification genes. Secondly, BAPN reduced collagen fibrotic markers Col1 and Col3. Additionally, LOX(L) inhibition blocked chondrocytes hypertrophic differentiation (Runx2 and COL10), pro-inflammatory IL-6 release and reactive oxygen species (ROS) production, all triggers of chondrocyte calcification. Through unbiased transcriptomic analysis we confirmed a positive correlation between LOX(L) genes and genes for calcification, hypertrophy and extracellular matrix catabolism. This association was conserved throughout species (mouse, human) and tissues that can undergo pathologic calcification (kidney, arteries, skin). Overall, LOX(L) play a critical role in the process of chondrocyte calcification and may be therapeutic targets to treat cartilage calcification in arthropathies.

Inhibiting de novo ceramide synthesis restores mitochondrial and protein homeostasis in muscle aging.

Disruption of mitochondrial function and protein homeostasis plays a central role in aging. However, how these processes interact and what governs their failure in aging remain poorly understood. Here, we showed that ceramide biosynthesis controls the decline in mitochondrial and protein homeostasis during muscle aging. Analysis of transcriptome datasets derived from muscle biopsies obtained from both aged individuals and patients with a diverse range of muscle disorders revealed that changes in ceramide biosynthesis, as well as disturbances in mitochondrial and protein homeostasis pathways, are prevalent features in these conditions. By performing targeted lipidomics analyses, we found that ceramides accumulated in skeletal muscle with increasing age across Caenorhabditis elegans, mice, and humans. Inhibition of serine palmitoyltransferase (SPT), the rate-limiting enzyme of the ceramide de novo synthesis, by gene silencing or by treatment with myriocin restored proteostasis and mitochondrial function in human myoblasts, in C. elegans, and in the skeletal muscles of mice during aging. Restoration of these age-related processes improved health and life span in the nematode and muscle health and fitness in mice. Collectively, our data implicate pharmacological and genetic suppression of ceramide biosynthesis as potential therapeutic approaches to delay muscle aging and to manage related proteinopathies via mitochondrial and proteostasis remodeling.

Boosting mitochondrial health to counteract neurodegeneration.

Mitochondrial health is based on a delicate balance of specific mitochondrial functions (e.g. metabolism, signaling, dynamics) that are impaired in neurodegenerative diseases. Rescuing mitochondrial function by selectively targeting mitochondrial stressors, such as reactive oxygen species, inflammation or proteotoxic insults ("bottom-up" approaches) thus is a widely investigated therapeutic strategy. While successful in preclinical studies, these approaches have largely failed to show clear clinical benefits. Promoting the capacity of mitochondria - and other cellular components - to restore a healthy cellular environment is a promising complementary or alternative approach. Herein, we provide a non-technical overview for neurologists and scientists interested in brain metabolism on neuroprotective strategies targeting mitochondria and focus on top-down interventions such as metabolic modulators, exercise, dietary restriction, brain stimulation and conditioning. We highlight general conceptual differences to bottom-up approaches and provide hypotheses on how these mechanistically comparatively poorly characterized top-down therapies may work, discussing notably mitochondrial stress responses and mitohormesis.

From the Bench to the Bedside: Branched Amino Acid and Micronutrient Strategies to Improve Mitochondrial Dysfunction Leading to Sarcopenia.

With extended life expectancy, the older population is constantly increasing, and consequently, so too is the prevalence of age-related disorders. Sarcopenia, the pathological age-related loss of muscle mass and function; and malnutrition, the imbalance in nutrient intake and resultant energy production, are both commonly occurring conditions in old adults. Altered nutrition plays a crucial role in the onset of sarcopenia, and both these disorders are associated with detrimental consequences for patients (e.g., frailty, morbidity, and mortality) and society (e.g., healthcare costs). Importantly, sarcopenia and malnutrition also share critical molecular alterations, such as mitochondrial dysfunction, increased oxidative stress, and a chronic state of low grade and sterile inflammation, defined as inflammageing. Given the connection between malnutrition and sarcopenia, nutritional interventions capable of affecting mitochondrial health and correcting inflammageing are emerging as possible strategies to target sarcopenia. Here, we discuss mitochondrial dysfunction, oxidative stress, and inflammageing as key features leading to sarcopenia. Moreover, we examine the effects of some branched amino acids, omega-3 PUFA, and selected micronutrients on these pathways, and their potential role in modulating sarcopenia, warranting further clinical investigation.

The exercise-induced long noncoding RNA CYTOR promotes fast-twitch myogenesis in aging.

Skeletal muscle displays remarkable plasticity upon exercise and is also one of the organs most affected by aging. Despite robust evidence that aging is associated with loss of fast-twitch (type II) muscle fibers, the underlying mechanisms remain to be elucidated. Here, we identified an exercise-induced long noncoding RNA, CYTOR, whose exercise responsiveness was conserved in human and rodents. Cytor overexpression in mouse myogenic progenitor cells enhanced myogenic differentiation by promoting fast-twitch cell fate, whereas Cytor knockdown deteriorated expression of mature type II myotubes. Skeletal muscle Cytor expression was reduced upon mouse aging, and Cytor expression in young mice was required to maintain proper muscle morphology and function. In aged mice, rescuing endogenous Cytor expression using adeno-associated virus serotype 9 delivery of CRISPRa reversed the age-related decrease in type II fibers and improved muscle mass and function. In humans, CYTOR expression correlated with type II isoform expression and was decreased in aged myoblasts. Increased CYTOR expression, mediated by a causal cis­expression quantitative trait locus located within a CYTOR skeletal muscle enhancer element, was associated with improved 6-min walk performance in aged individuals from the Helsinki Birth Cohort Study. Direct CYTOR overexpression using CRISPRa in aged human donor myoblasts enhanced expression of type II myosin isoforms. Mechanistically, Cytor reduced chromatin accessibility and occupancy at binding motifs of the transcription factor Tead1 by binding, and hence sequestering, Tead1. In conclusion, the long noncoding RNA Cytor was found to be a regulator of fast-twitch myogenesis in aging.

Phalloidin Staining of Actin Filaments for Visualization of Muscle Fibers in Caenorhabditis elegans.

Advances in C. elegans research have allowed scientists to recapitulate different human disorders, from neurodegenerative diseases to muscle dysfunction, in these nematodes. Concomitantly, the interest in visualizing organs affected by these conditions has grown, leading to the establishment of different antibody- and dye-based staining protocols to verify tissue morphology. In particular, the quality of muscle tissue has been largely used in nematodes as a readout for fitness and healthspan. Phalloidin derivatives, which are commonly used to stain actin filaments in cells and tissues, have been implemented in the context of C. elegans research for visualization of muscle fibers. However, the majority of the phalloidin-based protocols depend on fixation steps using harmful compounds, preparation of specific buffers, and large amounts of worms. Herein, we implemented a safer and more flexible experimental procedure to stain actin filaments in C. elegans using phalloidin-based dyes. Lyophilization of the worms followed by their acetone permeabilization allows bypassing the fixation process while also providing the opportunity to suspend the experiment at different steps. Moreover, by using conventional buffers throughout our protocol, we avoid the additional preparation of solutions. Finally, our protocol requires a limited number of worms, making it suitable for slow-growing C. elegans strains. Overall, this protocol provides an efficient, fast, and safer method to stain actin filaments and visualize muscle fibers in C. elegans. Graphic abstract: Schematic overview of phalloidin staining in C. elegans for assessing muscle fiber morphology.

NAD+ boosting reduces age-associated amyloidosis and restores mitochondrial homeostasis in muscle.

Aging is characterized by loss of proteostasis and mitochondrial homeostasis. Here, we provide bioinformatic evidence of dysregulation of mitochondrial and proteostasis pathways in muscle aging and diseases. Moreover, we show accumulation of amyloid-like deposits and mitochondrial dysfunction during natural aging in the body wall muscle of C. elegans, in human primary myotubes, and in mouse skeletal muscle, partially phenocopying inclusion body myositis (IBM). Importantly, NAD+ homeostasis is critical to control age-associated muscle amyloidosis. Treatment of either aged N2 worms, a nematode model of amyloid-beta muscle proteotoxicity, human aged myotubes, or old mice with the NAD+ boosters nicotinamide riboside (NR) and olaparib (AZD) increases mitochondrial function and muscle homeostasis while attenuating amyloid accumulation. Hence, our data reveal that age-related amyloidosis is a contributing factor to mitochondrial dysfunction and that both are features of the aging muscle that can be ameliorated by NAD+ metabolism-enhancing approaches, warranting further clinical studies.

NAD+ homeostasis in health and disease.

The conceptual evolution of nicotinamide adenine dinucleotide (NAD+) from being seen as a simple metabolic cofactor to a pivotal cosubstrate for proteins regulating metabolism and longevity, including the sirtuin family of protein deacylases, has led to a new wave of scientific interest in NAD+. NAD+ levels decline during ageing, and alterations in NAD+ homeostasis can be found in virtually all age-related diseases, including neurodegeneration, diabetes and cancer. In preclinical settings, various strategies to increase NAD+ levels have shown beneficial effects, thus starting a competitive race to discover marketable NAD+ boosters to improve healthspan and lifespan. Here, we review the basics of NAD+ biochemistry and metabolism, and its roles in health and disease, and we discuss current challenges and the future translational potential of NAD+ research.

Actualización en el manejo odontológico del paciente con patología hepática / Update on dental handling of the patient with liver disease

La enfermedad o disfunción hepática puede deberse a numerosas causas como infecciones adquiridas, patologías congénitas o el abuso de drogas. Cuando esta disfunción y el daño hepático se prolongan a lo largo del tiempo, puede desembocar en una cirrosis hepática, cuadro irreversible y de graves repercusiones para el enfermo. Las dos patologías hepáticas más frecuentes y principales causas de la cirrosis son la hepatitis o inflamación hepática, la cual se puede deber a numerosos factores siendo el más frecuente las infecciones por virus, y la enfermedad hepática alcohólica, provocada por el abuso de alcohol continuado durante un largo período de tiempo. El manejo odontológico de un paciente con alteraciones hepáticas supone un verdadero reto, ya que el hígado juega un papel vital en numerosas funciones metabólicas, como la secreción de bilis o la excreción de bilirrubina procedente del metabolismo de la hemoglobina. Un fallo en la función hepática puede suponer alteraciones en el metabolismo de aminoácidos, amoníaco, proteínas, hidratos de carbono y triglicéridos. Un paciente con patología hepática tendrá un metabolismo alterado de numerosos fármacos empleados habitualmente por el dentista, tendrá un mayor riesgo de hemorragia debido a anomalías en la síntesis de diferentes factores de coagulación, siendo además un paciente con mayor riesgo de infecciones. La gran repercusión de la enfermedad hepática, así como el notable desconocimiento de muchos profesionales odontólogos en su manejo, justifican este artículo donde se talla tanto las generalidades más importantes de esta entidad como sus principales manifestaciones orales y consideraciones en el manejo odontológico

Liver disease or dysfunction may be due to numerous causes such as acquired infections, congenital pathologies or drug abuse. When this dysfunction and liver damage are prolonged overtime, it can lead to hepatic cirrhosis, an irreversible condition and serious repercussions for the patient. The two most frequent liver diseases and major causes of cirrhosis are hepatitis or hepatic inflammation, which may be due to numerous factors being the most frequent virus infections, and alcoholic liver disease, caused by alcohol abuse continued during A long period of time. The dental management of a patient with liver disorders is a real challenge, since the liver plays a vital role in many metabolic functions, such as bile secretion or excretion of bilirubin from hemoglobin metabolism. A failure in liver function can lead to alterations in the metabolismof amino acids, ammonia, proteins, carbohydrates and triglycerides. A patient with liver disease will have an altered metabolism of numerous drugs commonly used by the dentist, will have a greater risk of hemorrhage due to abnormalities in the synthesis of different coagulation factors, being also a patient with a higher risk of infections. The great repercussion of liver disease, as well as the remarkable lack of knowledge of many dental professionals in its management, justify this article where it is detailed both the most important generalities of this entity as its main oral manifestations and considerations in dental management

Niacin: an old lipid drug in a new NAD+ dress.

Niacin, the first antidyslipidemic drug, has been at the center stage of lipid research for many decades before the discovery of statins. However, to date, despite its remarkable effects on lipid profiles, the clinical outcomes of niacin treatment on cardiac events is still debated. In addition to its historically well-defined interactions with central players of lipid metabolism, niacin can be processed by eukaryotic cells to synthesize a crucial cofactor, NAD+ NAD+ acts as a cofactor in key cellular processes, including oxidative phosphorylation, glycolysis, and DNA repair. More recently, evidence has emerged that NAD+ also is an essential cosubstrate for the sirtuin family of protein deacylases and thereby has an impact on a wide range of cellular processes, most notably mitochondrial homeostasis, energy homeostasis, and lipid metabolism. NAD+ achieves these remarkable effects through sirtuin-mediated deacetylation of key transcriptional regulators, such as peroxisome proliferator-activated receptor gamma coactivator 1-α, LXR, and SREBPs, that control these cellular processes. Here, we present an alternative point of view to explain niacin's mechanism of action, with a strong focus on the importance of how this old drug acts as a control switch of NAD+/sirtuin-mediated control of metabolism.

The RNA-Binding Protein PUM2 Impairs Mitochondrial Dynamics and Mitophagy During Aging.

Little information is available about how post-transcriptional mechanisms regulate the aging process. Here, we show that the RNA-binding protein Pumilio2 (PUM2), which is a translation repressor, is induced upon aging and acts as a negative regulator of lifespan and mitochondrial homeostasis. Multi-omics and cross-species analyses of PUM2 function show that it inhibits the translation of the mRNA encoding for the mitochondrial fission factor (Mff), thereby impairing mitochondrial fission and mitophagy. This mechanism is conserved in C. elegans by the PUM2 ortholog PUF-8. puf-8 knock-down in old nematodes and Pum2 CRISPR/Cas9-mediated knockout in the muscles of elderly mice enhances mitochondrial fission and mitophagy in both models, hence improving mitochondrial quality control and tissue homeostasis. Our data reveal how a PUM2-mediated layer of post-transcriptional regulation links altered Mff translation to mitochondrial dynamics and mitophagy, thereby mediating age-related mitochondrial dysfunctions.

Enhancing mitochondrial proteostasis reduces amyloid-ß proteotoxicity.

Alzheimer's disease is a common and devastating disease characterized by aggregation of the amyloid-ß peptide. However, we know relatively little about the underlying molecular mechanisms or how to treat patients with Alzheimer's disease. Here we provide bioinformatic and experimental evidence of a conserved mitochondrial stress response signature present in diseases involving amyloid-ß proteotoxicity in human, mouse and Caenorhabditis elegans that involves the mitochondrial unfolded protein response and mitophagy pathways. Using a worm model of amyloid-ß proteotoxicity, GMC101, we recapitulated mitochondrial features and confirmed that the induction of this mitochondrial stress response was essential for the maintenance of mitochondrial proteostasis and health. Notably, increasing mitochondrial proteostasis by pharmacologically and genetically targeting mitochondrial translation and mitophagy increases the fitness and lifespan of GMC101 worms and reduces amyloid aggregation in cells, worms and in transgenic mouse models of Alzheimer's disease. Our data support the relevance of enhancing mitochondrial proteostasis to delay amyloid-ß proteotoxic diseases, such as Alzheimer's disease.

Patogenia del cáncer oral por el virus del papiloma humano / Pathogenesis of oral cancer for human papiloma virus

Introducción: El cáncer oral representa el 1-2% de todos los cánceres del organismo, correspondiendo el 90% a carcinomas orales de células escamosas (COCE). Los factores de riesgo clásicamente implicados en el desarrollo del cáncer oral son la edad avanzada, el sexo masculino y la exposición prolongada a hábitos como el alcohol, el tabaco y la nuez de betel. Sin embargo, el incremento en los últimos años de la incidencia de COCE en pacientes jóvenes sin exposición a factores de riesgo clásicos ha puesto en manifiesto la presencia de otros posibles agentes etiopatogénicos, entre los que destaca el virus del papiloma humano (VPh). Objetivos: Poner de manifiesto el desarrollo molecular del COCE por la intervención del VPh como oncovirus y sus características. Resultados: Los estudios determinan el alto riesgo oncogénico que presenta el subtipo 16 y 18 del VPh actuando a través de sus proteínas E6 y E7, afectando directamente al p53, a la proteína del Retinoblastoma (pRb) y otras enzimas implicadas en la regulación del ciclo celular como la PI3K, alterándose así los procesos de apoptosis, proliferación y diferenciación celular. Conclusiones: El VPh juega un papel importante como carcinógeno en la aparición del COCE, con un pronóstico más favorable respecto a otros factores etiológicos. El proceso de oncogénesis en el desarrollo del COCE a partir del VPh está determinado por los subtipos de alto riesgo, así como la expresión de las proteínas virales E6 y E7, responsables de inhibir la actividad de los genes supresores de tumores del ciclo celular (AU)

Introduction: Oral cancer represents 1-2% of all cancer in the organism, 90% corresponding to oral squamous cell carcinomas (OSCC). Risk factors traditionally involved in the development of oral cancer are advanced age, male sex, and prolonged exposure to habits such as alcohol, tobacco, and betel nut. The increase in the incidence of OSCC in young patients without exposure to classical risk factors in recent years has revealed the presence of other possible etiopathogenic agents, especially the human Papilloma Virus (hPV). Objectives: Describe the molecular development of the OSCC by the hPV intervention as oncovirus and its characteristics. Results: Different studies show the high oncogenic risk of hPV 16 and 18 subtypes acting through their E6 and E7 proteins, directly affecting p53, Retinoblastoma protein (pRb) and other enzymes involved in the regulation of the cycle Cell as the PI3K, altering the processes of apoptosis, cell proliferation and differentiation. Conclusions: hPV plays an important role as a carcinogen in the onset of OSCC, with a more favorable prognosis regarding other etiological factors. The process of oncogenesis in the development of COCE from hPV is determined by the high risk subtypes as well as the expression of the viral proteins E6 and E7 responsible for inhibiting the activity of the cell cycle tumor suppressor genes (AU)