Global phosphoproteomic profiling reveals perturbed signaling in a mouse model of dilated cardiomyopathy

Phospholamban (PLN) plays a central role in Ca2+ homeostasis in cardiac myocytes through regulation of the sarco(endo)plasmic reticulum Ca2+-ATPase 2A (SERCA2A) Ca2+ pump. An inherited mutation converting arginine residue 9 in PLN to cysteine (R9C) results in dilated cardiomyopathy (DCM) in humans and transgenic mice, but the downstream signaling defects leading to decompensation and heart failure are poorly understood. Here we used precision mass spectrometry to study the global phosphorylation dynamics of 1,887 cardiac phosphoproteins in early affected heart tissue in a transgenic R9C mouse model of DCM compared with wild-type littermates. Dysregulated phosphorylation sites were quantified after affinity capture and identification of 3,908 phosphopeptides from fractionated whole-heart homogenates. Global statistical enrichment analysis of the differential phosphoprotein patterns revealed selective perturbation of signaling pathways regulating cardiovascular activity in early stages of DCM. Strikingly, dysregulated signaling through the Notch-1 receptor, recently linked to cardiomyogenesis and embryonic cardiac stem cell development and differentiation but never directly implicated in DCM before, was a prominently perturbed pathway. We verified alterations in Notch-1 downstream components in early symptomatic R9C transgenic mouse cardiomyocytes compared with wild type by immunoblot analysis and confocal immunofluorescence microscopy. These data reveal unexpected connections between stress-regulated cell signaling networks, specific protein kinases, and downstream effectors essential for proper cardiac function

Gene expression profiling of two fish helminths throughout their complex life cycles. Are parasite’s life stages genetically decoupled?

Komplexe Lebenszyklen sind eine häufige, aber anspruchsvolle Lebensweise von Parasiten. Parasiten mit komplexen Lebenszyklen infizieren nacheinander mehrere Wirte und passen sich an verschiedene ökologische Nischen an. Werden in diesem Szenario dieselben Gene in allen Wirten einheitlich exprimiert? Die Hypothese der adaptiven Entkopplung besagt, dass verschiedene Stadien in einem komplexen Lebenszyklus genetisch und evolutionär unabhängig sind, was bedeutet, dass die Selektion auf Parasitenmerkmale in einem Wirt keine Auswirkungen auf Merkmale in anderen Wirten hat. Wir haben diese Hypothese anhand von zwei Parasitenarten getestet: dem Bandwurm Schistocephalus solidus und dem Fadenwurm Camallanus lacustris. Die Transkriptomsequenzierung wurde an Proben während ihrer komplexen Lebenszyklen durchgeführt. Die Genexpressionsanalyse wurde durchgeführt, um Gene zu identifizieren, die zwischen den Wirten, zwischen den Funktionsstadien und zwischen den Bedingungen unterschiedlich exprimiert werden. Darüber hinaus wurde mit einer Analyse der Anreicherung von Gensätzen untersucht, ob ähnliche biologische Funktionen von ähnlichen Genen in verschiedenen Stadien kodiert werden. Unsere Ergebnisse zeigen signifikante Unterschiede in der Genexpression zwischen den verschiedenen Stadien, wobei keine positive Korrelation zwischen Stadien mit derselben Aufgabe oder demselben Wirt beobachtet wurde. Gene, die in einem Stadium hochreguliert (oder herunterreguliert) werden, werden in anderen Stadien nicht in ähnlicher Weise exprimiert. Dies spricht für die Unabhängigkeit der einzelnen Stadien bei der Genexpression, die es den Parasiten ermöglicht, ihren Phänotyp als Reaktion auf unterschiedlichen Selektionsdruck zu modulieren. Diese Ergebnisse bestätigen die Hypothese der adaptiven Entkopplung bei parasitären Würmern und bieten Einblicke in den evolutionären Erfolg dieser Lebensweise.Complex life cycles are a common but demanding lifestyle among parasites. Parasites with complex life cycles sequentially infect multiple hosts, adapting to various ecological niches using information encoded within a single genome. In this scenario, are the same genes expressed consistently across all hosts, as might occur when parasite stages perform similar functions? The adaptive decoupling hypothesis posits that different stages in a complex life cycle are genetically and evolutionarily independent, meaning selection on parasite traits in one host does not affect traits in other hosts. We tested this hypothesis using two species of parasites: the tapeworm Schistocephalus solidus and the nematode Camallanus lacustris, both of which have three-host life cycles. Transcriptome sequencing was performed on samples throughout their complex life cycles, generating transcriptomes from 10 stages of S. solidus and 7 stages of C. lacustris. Gene expression analysis was conducted to identify genes differentially expressed between hosts, between functional stages, and between conditions. Additionally, gene set enrichment analysis assessed whether similar biological functions are encoded by similar genes across stages. Our findings demonstrate significant differences in gene expression across stages, with no positive correlation observed between stages sharing the same task or host. The highest correlation occurred between stages sampled close in time. In conclusion, the lack of positive correlation between different life cycle stages indicates that genes up-regulated (or down-regulated) in one stage are not similarly expressed in other stages. This evidence supports the independence of each stage in gene expression, enabling parasites to modulate their phenotype in response to different selective pressures. These findings corroborate the adaptive decoupling hypothesis in parasitic worms with complex life cycles, offering insights into the evolutionary success of this lifestyle

Mexican petroleum since nationalization.

Thesis (M.A.)--Boston UniversityThe first successful commercial exploitation of Mexican petroleum took place during the last decade of Porfirio Diaz's regime (1900-1910). Favorable concessions were given to British and American oil companies. Under these conditions, Mexico by 1921 had become the world's second largest oil producing country. The Revolution of 1910-1920 brought about profound changes in Mexico. There emerged a highly nationalistic orientation toward subsoil wealth. As a result, Article 27 of the 1917 Constitution vested ownership and control of mineral and petroleum deposits in the nation. In addition, there arose in post-Revolutionary Mexico a strong labor movement generally backed by the government. Under these new conditions, friction developed between the labor movement and Mexican government, on the one hand, and the foreign petroleum companies on the other, leading to the expropriation of the oil companies by the Mexican government on March 18, 1938. [TRUNCATED

Proteomics and Mass Spectrometry: What Have We Learned About The Heart?

The emergence of new platforms for the discovery of innovative therapeutics has provided a means for diagnosing cardiac disease in its early stages. Taking into consideration the global health burden of cardiac disease, clinicians require innovations in medical diagnostics that can be used for risk stratification. Proteomic based studies offer an avenue for the discovery of proteins that are differentially regulated during disease; such proteins could serve as novel biomarkers of the disease state. For instance, in clinical practice, the abundance of such biomarkers in blood could be correlated with the severity of the disease state. As such, early detection of biomarkers would enable an improvement in patient prognosis. In this review, we outline advancements in various proteomic platforms used to study the disease proteome and their applications to the field of clinical medicine. Specifically, we highlight the contributions of proteomic-based profiling experiments to the analysis of cardiovascular diseases

Distinct regions in the 3′ untranslated region are responsible for targeting and stabilizing utrophin transcripts in skeletal muscle cells

In this study, we have sought to determine whether utrophin transcripts are targeted to a distinct subcellular compartment in skeletal muscle cells, and have examined the role of the 3′ untranslated region (UTR) in regulating the stability and localization of utrophin transcripts. Our results show that utrophin transcripts associate preferentially with cytoskeleton-bound polysomes via actin microfilaments. Because this association is not evident in myoblasts, our findings also indicate that the localization of utrophin transcripts with cytoskeleton-bound polysomes is under developmental influences. Transfection of LacZ reporter constructs containing the utrophin 3′UTR showed that this region is critical for targeting chimeric mRNAs to cytoskeleton-bound polysomes and controlling transcript stability. Deletion studies resulted in the identification of distinct regions within the 3′UTR responsible for targeting and stabilizing utrophin mRNAs. Together, these results illustrate the contribution of posttranscriptional events in the regulation of utrophin in skeletal muscle. Accordingly, these findings provide novel targets, in addition to transcriptional events, for which pharmacological interventions may be envisaged to ultimately increase the endogenous levels of utrophin in skeletal muscle fibers from Duchenne muscular dystrophy (DMD) patients

Thermodynamic stability, unfolding kinetics, and aggregation of the N-terminal actin-binding domains of utrophin and dystrophin.

Muscular dystrophy (MD) is the most common genetic lethal disorder in children. Mutations in dystrophin trigger the most common form of MD, Duchenne, and its allelic variant Becker MD. Utrophin is the closest homologue and has been shown to compensate for the loss of dystrophin in human disease animal models. However, the structural and functional similarities and differences between utrophin and dystrophin are less understood. Both proteins interact with actin through their N-terminal actin-binding domain (N-ABD). In this study, we examined the thermodynamic stability and aggregation of utrophin N-ABD and compared with that of dystrophin. Our results show that utrophin N-ABD has spectroscopic properties similar to dystrophin N-ABD. However, utrophin N-ABD has decreased denaturant and thermal stability, unfolds faster, and is correspondingly more susceptible to proteolysis, which might account for its decreased in vivo half-life compared to dystrophin. In addition, utrophin N-ABD aggregates to a lesser extent compared with dystrophin N-ABD, contrary to the general behavior of proteins in which decreased stability enhances protein aggregation. Despite these differences in stability and aggregation, both proteins exhibit deleterious effects of mutations. When utrophin N-ABD mutations analogous in position to the dystrophin disease-causing mutations were generated, they behaved similarly to dystrophin mutants in terms of decreased stability and the formation of cross-β aggregates, indicating a possible role for utrophin mutations in disease mechanisms

Computational and informatics strategies for identification of specific protein interaction partners in affinity purification mass spectrometry experiments

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/92060/1/pmic7070.pd

The predictive value of fruit juice in the esophagus-pleural fistula.

Esophageal-pleural fistula is a rare and challenging condition to diagnose and requires strong clinical suspicion in order to be recognized promptly. Chest computed tomography (CT) with contrast medium for explain abbreviation (OS) is the gold standard for diagnosis. The definitive therapy is purely surgical, except for a few selected cases that benefit from endoscopic therapy. Our case involves a 45-year-old woman who came to the Emergency Department with dyspnea and thoracalgia. Chest X-ray and high-resolution CT showed empyema and pleural effusion to the left hemithorax. The lack of improvement despite the therapy and a subsequent clinical finding gave rise to the suspicion of esophageal-pleural fistula, confirmed with CT with contrast medium for OS. In this case, we opted for endoscopy correction of the esophageal defects. The diagnostic delay and the pre-existing comorbidities (previous kidney transplant for chronic kidney disease from lupus nephritis, high blood pressure, familiarity with Ischemic cardiomyopathy) could justify the inauspicious course of our case