Strategies to treat cachexia are still at its infancy. Enhanced muscle protein breakdown and ubiquitin‐proteasome system are common features of cachexia associated with chronic conditions including ...lung cancer (LC). Poly(ADP‐ribose) polymerases (PARP), which play a major role in chromatin structure regulation, also underlie maintenance of muscle metabolism and body composition. We hypothesized that protein catabolism, proteolytic markers, muscle fiber phenotype, and muscle anabolism may improve in respiratory and limb muscles of LC‐cachectic Parp‐1‐deficient (Parp‐1−/−) and Parp‐2−/− mice. In diaphragm and gastrocnemius of LC (LP07 adenocarcinoma) bearing mice (wild type, Parp‐1−/−, and Parp‐2−/−), PARP activity (ADP‐ribose polymers, pADPr), redox balance, muscle fiber phenotype, apoptotic nuclei, tyrosine release, protein ubiquitination, muscle‐specific E3 ligases, NF‐κB signaling pathway, markers of muscle anabolism (Akt, mTOR, p70S6K, and mitochondrial DNA) were evaluated along with body and muscle weights, and limb muscle force. Compared to wild type cachectic animals, in both respiratory and limb muscles of Parp‐1−/− and Parp‐2−/− cachectic mice: cancer induced‐muscle wasting characterized by increased PARP activity, protein oxidation, tyrosine release, and ubiquitin‐proteasome system (total protein ubiquitination, atrogin‐1, and 20S proteasome C8 subunit) were blunted, the reduction in contractile myosin and atrophy of the fibers was attenuated, while no effects were seen in other structural features (inflammatory cells, internal or apoptotic nuclei), and markers of muscle anabolism partly improved. Activation of either PARP‐1 or ‐2 is likely to play a role in muscle protein catabolism via oxidative stress, NF‐κB signaling, and enhanced proteasomal degradation in cancer‐induced cachexia. Therapeutic potential of PARP activity inhibition deserves attention.
The study findings imply that activation of either PARP‐1 or ‐2 is likely to play a relevant role in muscle protein catabolism via oxidative stress, NF‐κB signaling, and enhanced proteasomal degradation in cancer‐induced cachexia. Despite the potential limitations of PARP activity inhibition, since it plays a key role in DNA maintenance, exploration of its reliability, and likely applicability as a possible target for future therapeutic interventions deserves attention in models of cancer‐induced cachexia.
Chronic metabolic impairment and oxidative stress are associated with the pathogenesis of axonal dysfunction in a growing number of neurodegenerative conditions. To investigate the intertwining of ...both noxious factors, we have chosen the mouse model of adrenoleukodystrophy (X-ALD), which exhibits axonal degeneration in spinal cords and motor disability. The disease is caused by loss of function of the ABCD1 transporter, involved in the import and degradation of very long-chain fatty acids (VLCFA) in peroxisomes. Oxidative stress due to VLCFA excess appears early in the neurodegenerative cascade.
In this study, we demonstrate by redox proteomics that oxidative damage to proteins specifically affects five key enzymes of glycolysis and TCA (Tricarboxylic acid) cycle in spinal cords of Abcd1(-) mice and pyruvate kinase in human X-ALD fibroblasts. We also show that NADH and ATP levels are significantly diminished in these samples, together with decrease of pyruvate kinase activities and GSH levels, and increase of NADPH.
Treating Abcd1(-) mice with the antioxidants N-acetylcysteine and α-lipoic acid (LA) prevents protein oxidation; preserves NADH, NADPH, ATP, and GSH levels; and normalizes pyruvate kinase activity, which implies that oxidative stress provoked by VLCFA results in bioenergetic dysfunction, at a presymptomatic stage.
Our results provide mechanistic insight into the beneficial effects of antioxidants and enhance the rationale for translation into clinical trials for X-adrenoleukodystrophy.
New Findings
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What is the central question of this study?
We explored whether experimental cancer‐induced cachexia may alter mitochondrial respiratory chain (MRC) complexes and oxygen uptake in ...respiratory and peripheral muscles, and whether signalling pathways, proteasome and oxidative stress influence that process.
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What is the main finding and what is its importance?
In cancer cachectic mice, MRC complexes and oxygen consumption were decreased in the diaphragm and gastrocnemius. Blockade of nuclear factor‐κB and mitogen‐activated protein kinase actions partly restored the muscle mass and force and corrected the MRC dysfunction, while concomitantly reducing tumour burden. Antioxidants improved mitochondrial oxygen consumption without eliciting effects on the loss of muscle mass and force or the tumour size, whereas bortezomib reduced tumour burden without influencing muscle mass and strength or MRC function.
Abnormalities in mitochondrial content, morphology and function have been reported in several muscle‐wasting conditions. We specifically explored whether experimental cancer‐induced cachexia may alter mitochondrial respiratory chain (MRC) complexes and oxygen uptake in respiratory and peripheral muscles, and whether signalling pathways, proteasomes and oxidative stress may influence that process. We evaluated complex I, II and IV enzyme activities (specific activity assays) and MRC oxygen consumption (polarographic measurements) in diaphragm and gastrocnemius of cachectic mice bearing the LP07 lung tumour, with and without treatment with N‐acetylcysteine, bortezomib and nuclear factor‐κB (sulfasalazine) and mitogen‐activated protein kinases (MAPK, U0126) inhibitors (n= 10 per group for all groups). Whole‐body and muscle weights and limb muscle force were also assessed in all rodents at baseline and after 1 month. Compared with control animals, cancer cachectic mice showed a significant reduction in body weight gain, smaller sizes of the diaphragm and gastrocnemius, lower muscle strength, decreased activity of complexes I, II and IV and decreased oxygen consumption in both muscles. Blockade of nuclear factor‐κB and MAPK actions restored muscle mass and force and corrected the MRC dysfunction in both muscles, while partly reducing tumour burden. Antioxidants improved mitochondrial oxygen uptake without eliciting significant effects on the loss of muscle mass and force or tumour size, whereas the proteasome inhibitor reduced tumour burden without significantly influencing muscle mass and strength or mitochondrial function. In conclusion, nuclear factor‐κB and MAPK signalling pathways modulate muscle mass and performance and MRC function of respiratory and limb muscles in this model of experimental cancer cachexia, thus offering targets for therapeutic intervention.
Rare diseases (RDs) as a whole affect a huge number of individuals although each specific condition comprises a low number of individuals. As a consequence, funds allocated to expand research to all ...conditions are often limited. Several initiatives have emerged to invest more resources for research in RDs, but patients express unmet needs regarding educational initiatives, awareness support, and psychosocial resources. We developed an educational training program in the format of weekly sessions covering basic medical scientific knowledge and psychosocial aspects of RDs. The aim of this initiative was to assess its overall impact regarding knowledge, psychological issues, and participant satisfaction. Items were evaluated through surveys before and after the sessions. Here, we report the experience and impact of two editions of this initiative with a total of 37 participants. Our results show improvements in knowledge and better management of the psychological impact. Moreover, participants were able to exchange experiences and concerns, most of which were shared even though the RDs were different. Overall, the program was evaluated by the participants as a highly beneficial experience and all of them were interested in attending advanced editions.
Background/Objectives: Non-Invasive prenatal test (NIPT) is used as a universal or contingent test after prior risk assessment. Screening is mainly performed for common trisomies (T21, T13, T18), ...although other chromosomal anomalies may be detected. Our objective was to study the performance of GWNIPT in the detection of chromosomal abnormalities in pregnancies in which an invasive prenatal study was performed and in early pregnancy losses, in comparison with the reference test. Method: VeriSeqTM NIPT Solution v2, a genome-wide NIPT (GWNIPT), was performed prior to invasive testing in fetal diagnostic study cases (FDS, n = 155) and in early pregnancy losses (EPL, n = 68). Results: In the FDS group, the diagnostic test (QFPCR, array and karyotype) detected anomalies in 32 pregnancies (21%), in twenty of them (61%) also detected by GWNIPT. Eleven of the twelve cases undetected by GWNIPT were balanced translocations (n = 4) or deletions/duplications <7 Mb (n = 7). In the EPL group, GWNIPT detected anomalies in 46% of cases (31/68) but comparison with reference test (QFPCR and karyotype) in products of conception (POC) was only possible in 18 cases. Concordant results between POC and GWNIPT test were obtained in 16 of the 18 cases. In EPL, with GWNIPT testing, common trisomies accounted for 25.8% of cases (8/31), rare trisomies 54.8% (17/31) and microdeletions/duplications 16.1% (5/31). Conclusions: The GWNIPT test may be useful in clinical practice in prenatal and in EPL’s genetic diagnosis when the appropriate sample is not available.
Abstract
Methods to reconstruct the mitochondrial DNA (mtDNA) sequence using short-read sequencing come with an inherent bias due to amplification and mapping. They can fail to determine the phase of ...variants, to capture multiple deletions and to cover the mitochondrial genome evenly. Here we describe a method to target, multiplex and sequence at high coverage full-length human mitochondrial genomes as native single-molecules, utilizing the RNA-guided DNA endonuclease Cas9. Combining Cas9 induced breaks, that define the mtDNA beginning and end of the sequencing reads, as barcodes, we achieve high demultiplexing specificity and delineation of the full-length of the mtDNA, regardless of the structural variant pattern. The long-read sequencing data is analysed with a pipeline where our custom-developed software, baldur, efficiently detects single nucleotide heteroplasmy to below 1%, physically determines phase and can accurately disentangle complex deletions. Our workflow is a tool for studying mtDNA variation and will accelerate mitochondrial research.
Primary ciliary dyskinesia (PCD) is characterized by an alteration in the ciliary structure causing difficulty in the clearance of respiratory secretions. Diagnosis is complex and based on a ...combination of techniques. The objective of this study was to design a gene panel including all known causative genes, and to corroborate their diagnostic utility in a cohort of Spanish patients.
This was a multicenter cross-sectional study of patients with a high suspicion of PCD according to European Respiratory Society criteria. We designed a gene panel for massive sequencing using SeqCap EZ capture technology that included 44 genes associated with PCD.
We included 79 patients, 53 of whom had a diagnosis of confirmed or highly probable PCD. The sensitivity of the gene panel was 81.1%, with a specificity of 100%. Candidate variants were found in some of the genes of the panel in 43 patients with PCD, 51.2% (22/43) of whom were homozygotes and 48.8% (21/43) compound heterozygotes. The most common causative genes were DNAH5 and CCDC39. We found 52 different variants, 36 of which were not previously described in the literature.
The design and implementation of a tailored gene panel produces a high yield in the genetic diagnosis of PCD. This panel provides a better understanding of the causative factors involved in these patients and lays down the groundwork for future therapeutic approaches.
La discinesia ciliar primaria (DCP) es una enfermedad caracterizada por una alteración en la estructura ciliar que impide el correcto aclaramiento de las secreciones respiratorias. Su diagnóstico es complejo y se basa en una combinación de técnicas. El objetivo de este estudio fue diseñar un panel de genes incluyendo todos los genes causantes conocidos y comprobar su utilidad diagnóstica en una cohorte de pacientes españoles.
Estudio transversal multicéntrico de pacientes con sospecha elevada de DCP, aplicando los criterios de la European Respiratory Society. Diseño de un panel de genes para secuenciación masiva con la tecnología de captura SeqCap EZ technology, incluyendo 44 genes relacionados con la DCP.
Se incluyó a 79 pacientes de los que 53 presentaron un diagnóstico de DCP confirmado o muy probable. La sensibilidad del panel de genes fue del 81,1% con una especificidad del 100%. Se encontraron variantes candidatas en alguno de los genes del panel en 43 de los pacientes con DCP, siendo 51,2% (22/43) homocigotos y 48,8% (21/43) heterocigotos compuestos. Los genes causales más frecuentes fueron DNAH5 y CCDC39. Encontramos 52 variantes distintas, 36 no descritas previamente en la literatura.
El diseño y la implementación de un panel de genes a medida tiene un alto rendimiento diagnóstico genético de la DCP, lo que permite conocer mejor la afectación causal de estos pacientes y sentar las bases para futuros abordajes terapéuticos.
Palmoplantar keratoderma (PPK) is a multi-faceted skin disorder characterized by the thickening of the epidermis and abrasions on the palms and soles of the feet. Among the genetic causes, biallelic ...pathogenic variants in the FAM83G gene have been associated with PPK in dogs and humans. Here, a novel homozygous variant (c.794G>C, p.Arg265Pro) in the FAM83G gene, identified by whole exome sequencing in a 60-year-old female patient with PPK, is reported. The patient exhibited alterations in the skin of both hands and feet, dystrophic nails, thin, curly and sparse hair, long upper eyelid eyelashes, and poor dental enamel. FAM83G activates WNT signalling through association with ser/thr protein kinase CK1α. When expressed in FAM83G −/− DLD1 colorectal cancer cells, the FAM83G R265P variant displayed poor stability, a loss of interaction with CK1α and attenuated WNT signalling response. These defects persisted in skin fibroblast cells derived from the patient. Our findings imply that the loss of FAM83G-CK1α interaction and subsequent attenuation of WNT signalling underlie the pathogenesis of PPK caused by the FAM83G R265P variant.
Monocyte exposure to mitochondrial Danger Associated Molecular Patterns (DAMPs), including mitochondrial DNA (mtDNA), induces a transient state in which these cells are refractory to further ...endotoxin stimulation. In this context, IRAK-M up-regulation and impaired p65 activity were observed. This phenomenon, termed endotoxin tolerance (ET), is characterized by decreased production of cytokines in response to the pro-inflammatory stimulus. We also show that monocytes isolated from patients with myocardial infarction (MI) exhibited high levels of circulating mtDNA, which correlated with ET status. Moreover, a significant incidence of infection was observed in those patients with a strong tolerant phenotype. The present data extend our current understanding of the implications of endotoxin tolerance. Furthermore, our data suggest that the levels of mitochondrial antigens in plasma, such as plasma mtDNA, should be useful as a marker of increased risk of susceptibility to nosocomial infections in MI and in other pathologies involving tissue damage.
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