Basal Complex Research Articles

Proteomics Links Ubiquitin Chain Topology Change to Transcription Factor Activation.

A surprising complexity of ubiquitin signaling has emerged with identification of different ubiquitin chain topologies. However, mechanisms of how the diverse ubiquitin codes control biological processes remain poorly understood. Here, we use quantitative whole-proteome mass spectrometry to identify yeast proteins that are regulated by lysine 11 (K11)-linked ubiquitin chains. The entire Met4 pathway, which links cell proliferation with sulfur amino acid metabolism, was significantly affected by K11 chains and selected for mechanistic studies. Previously, we demonstrated that a K48-linked ubiquitin chain represses the transcription factor Met4. Here, we show that efficient Met4 activation requires a K11-linked topology. Mechanistically, our results propose that the K48 chain binds to a topology-selective tandem ubiquitin binding region in Met4 and competes with binding of the basal transcription machinery to the same region. The change to K11-enriched chain architecture releases this competition and permits binding of the basal transcription complex to activate transcription.

Abstract 886: Mitochondrial Stress Response by Lonp1 in Cardiac Function and Protection

LonP1 is a mitochondrial protease that is crucial for maintaining cardiac mitochondrial homeostasis. We recently showed that LonP1 mediates cardioprotection during cardiac ischemia-reperfusion (I/R) by reducing oxidative stress and infarct size. We hypothesize that LonP1 promotes mitochondrial biogenesis during cardiac differentiation and development and protects the heart from oxidative injury by recalibrating bioenergetics. Here, we employ human induced pluripotent stem cells differentiated into cardiomyocytes (iPSC-CMs), rat neonatal ventricular myocytes (rNVMs), and mouse models with cardiac-specific LonP1 overexpression (LonTg) and heterozygous LonP1 knockout ( LONP1 +/- ). In iPSC-CMs, LonP1 is induced 4.8-fold at 39 vs. 12 days after differentiation. During the maturation of murine hearts, LonP1 is increased 4.6-fold at 3 months vs. during 1 day. Upregulation was also observed in rNVMs in which LonP1 is induced 5- fold after 5 days culturing, compared to 0 days. LonP1 induction in rNVMs is accompanied by substantial 2-fold upregulation of mitochondrial transcripts, MT-CYB and MT-COI. However, the levels of another mitochondrial matrix protease ClpP was not altered, suggesting that LonP1 specifically may play an important role during mitochondrial biogenesis and proteostasis in the heart. In vivo, LonTg protected the myocardium against ischemia-reperfusion (I/R) injury by preventing oxidative damage. In LonTg hearts, basal complex I activity was significantly (p<0.05) reduced (Ntg-0.01 ± 0.001 vs. LonTg-0.0078 ± 0.001 mOD/min), as well as during I/R (Ntg-0.0139 ± 0.0005 vs LonTg-0.0102 ± 0.001 mOD/min) (n=3 each). However, no difference was observed in the complex I activity in LONP1 +/+ (0.0118 ± 0.0 mOD/min) and LONP1 +/- (0.0121 ± 0.0 mOD/min) mice (n=3 each). In addition, our preliminary native gel data of LonTg hearts shows a 40% reduction (n=1) in the levels of mitochondrial supercomplexes, compared to NTg hearts (n=4). Further studies are underway to explore the role of LonP1 during differentiation, and in response to mitochondrial cardiac stress. Together, our findings show a novel role of LonP1 in regulating cardiac function during mitochondrial biogenesis and in mitigating cardiac stress-induced injury.

An essential contractile ring protein controls cell division in Plasmodium falciparum

During the blood stage of human malaria, Plasmodium falciparum parasites divide by schizogony—a process wherein components for several daughter cells are produced within a common cytoplasm and then segmentation, a synchronized cytokinesis, produces individual invasive daughters. The basal complex is hypothesized to be required for segmentation, acting as a contractile ring to establish daughter cell boundaries. Here we identify an essential component of the basal complex which we name PfCINCH. Using three-dimensional reconstructions of parasites at electron microscopy resolution, we show that while parasite organelles form and divide normally, PfCINCH-deficient parasites develop inviable conjoined daughters that contain components for multiple cells. Through biochemical evaluation of the PfCINCH-containing complex, we discover multiple previously undescribed basal complex proteins. Therefore, this work provides genetic evidence that the basal complex is required for precise segmentation and lays the groundwork for a mechanistic understanding of how the parasite contractile ring drives cell division.

Characterization of the NCoR1 complex and its association with the molecular control of the mitochondrial biogenesis process

Metabolic homeostasis is regulated transcriptionally through the interaction between transcription factors, co‐regulators and proteins of the basal transcriptional complex. Nuclear co‐regulators work either as transcriptional repressors or as transcriptional activators and, therefore, are strictly regulated to synchronize metabolic pathways to environmental stimuli. Preliminary results from our laboratory have indicated that the NCoR1 co‐repressor plays an important role in the regulation of mitochondrial biogenesis and oxidative metabolism in muscle cells. During the differentiation process of C2C12 muscle cells, the expression of the NCoR1 repressor is reduced favoring the process of mitochondrial biogenesis. While, overexpression of NCoR1 negatively affects the oxidative characteristics of these cells. These observations suggest that NCoR1 plays a central role in binding the nuclear receptor to the transcriptional program of mitochondrial biogenesis. In this way, we are proposing here study to identify and characterize NCoR1 protein (s) involved in the regulation of mitochondrial biogenesis in MEF cells. Thus, we hope to identify potential therapeutic targets in the management of obesity and diabetes. The design will be performed through the following experimental steps: 1) Co‐immunoprecipitation/proteome of the NCoR1 complex; 2) In silico analysis of target candidates; 3) Identification of the target through functional/biochemical tests. Finally we intend to explore the target interface/NCoR1 as therapeutic potential in experimental models of insulin resistance/obesity. The overexpression of NCoR1 was confirmed by PCR and western blotting (Figure 1). After NCoR1 co‐imunoprecipitation (Fig. 2), cellular extract was submitted to mass spectrometry (LC‐MS/MS ) analysis and at least 15 targets were identified (Table 1). The identified proteins were listed according to (A) cellular components; (B) Molecular function; (C) Biological process (Fig. 3). Interactome analysis also demonstrated physical interaction among NcoR1 and indentified proteins including Hdac3, Tbl1xr1, GPS2 and Chd8 (Fig. 4). This analysis revealed potential candidates to control mitochondrial function/biogenesis in MEF cells.Support or Funding InformationThis work was supported by grant from Fundação de Amparo à Pesquisa do estado de São Paulo – FAPESP (2016/23008‐5), Capes and CNpq.This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

The role of SAGA in the transcription and export of mRNA

SAGA/TFTC, which is a histone acetyltransferase complex, plays an important role in the regulation of transcription. We have identified that the metazoan TFTC/STAGA complexes had histone H2A and H2B deubiquitinase activity that is carried out by a DUBm (deubiquitination module). We studied the DUBm of SAGA in Drosophila melanogaster and identified Drosophila homologs of yeast DUBm components. Two subunits of DUBm (Sus1/ENY2 and Sgf11) were shown to have functions separate from DUBm function. Thus, Sus1/ENY2 was shown to be present in several different complexes. Sgf11 was found to be associated with the cap-binding complex (CBC) and recruited onto growing messenger ribonucleic acid (mRNA). Also, we have shown that Sgf11 interacted with the TREX-2/AMEX mRNA export complex and was essential for mRNA export from the nucleus. Immunostaining of the polytene chromosomes of Drosophila larvae revealed that Sgf11 is present at the sites of localization of snRNA genes. It was also found in immunostaining experiments that dPbp45, the subunit of the PBP complex, the key player in the snRNA transcription process, is associated not only with the snRNA gene localization sites, but with other sites of active transcription by PolII. We also revealed that Sgf11 was present at many active transcription sites in interbands and puffs on polytene chromosomes, Sgf11 was localized at all Brf1 (the component of the RNA polymerase III basal transcription complex) sites. We concluded that SAGA coactivated transcription of both the PolII and PolIII-dependent snRNA genes.

A remarkable Late Saalian (MIS 6) loess (dust) accumulation in the Lower Danube at Harletz (Bulgaria)

While numerous high-resolution studies concerning Last Glacial aeolian sequences are available for Europe, the approach of the penultimate glacial in this geographical area is still poorly developed. In order to bridge this gap, this study focuses on the Bulgarian sequence of Harletz, along the Danube River, where extremely high sedimentation rates allow the depiction of high-resolution signals during MIS 6. At Harletz in NW Bulgaria on the western bank of the Ogosta River (tributary of the Danube) a 20 m thick loess-palaeosols section was cleaned and sampled for a multi-disciplinary study and detailed pedostratigraphic approach. High-resolution continuous bulk sampling (5 cm) was carried out to characterise sedimentary grain size, magnetic properties (including magnetic susceptibility and its frequency dependence), colour reflectance (1 cm), and organic carbon. Geochronological control is based on 16 samples collected for OSL and MET-pIRIR dating. Using a cyclo-stratigraphic approach of the sequence combined with dating constraints provided by both MET-pIRIR dates and the age of a tephra layer occurring at a depth of 12 m within the main loess unit, we can demonstrate that the Harletz section exhibits a 10 m thick Late Saalian (Marine Isotope Stage 6, MIS 6) loess accumulation unique in Europe. The lower part of the main loess unit is 4 m thick and overlies a basal brown soil complex allocated to MIS 7, which includes an exceptionally thick (4 m) and detailed succession of loess and four incipient soil horizons never described in European loess until now. The closest and best-dated high-resolution palaeoenvironmental archive suitable for comparison comes from Lake Ohrid located about 400 km to the SW of Harletz. The Ohrid palynological record shows a progressive step-by-step evolution in climate and in environmental change during the transition between MIS 7 and MIS 6 from which a parallel with the Harletz pedosedimentary succession can be proposed. During the younger part of MIS 6 (160-129ka), steppe vegetation with abundant herbs (Artemisia) is dominant in the Lake Ohrid record, in good accordance with a global enhancement of aeolian dynamics, especially well recorded in sections located close to the Danube River from Serbia to Bulgaria and Romania (L2 loess). According to interpretations stemming from this study, the silts and fine sands building the Harletz loess section would have been transported from the Danube braided river system located (at that time) at about 4.5 km to the NW. Based on our data, the main loess units are characterised by a very low to a total absence of coarse sand particles. By contrast, during the Eemian interglacial (MIS 5e), and to a lesser extent throughout MIS 5 and during MIS 3 interstadials, the long distance transport of silt and fine sand particles is stopped and a weak aeolian sedimentation is likely driven by north-easterly winds transporting coarse sand grains from the proximal Ogosta River sandy banks. Finally, the weak development of Last Glacial loess (4 m max.) likely results from a rapid infilling of the sedimentary trap during the Saalian, then followed by a strong anthropogenic erosion of the topsoil and of the upper part of the loess profile since the Early Holocene (Neolithic).

Cartography of hevin-expressing cells in the adult brain reveals prominent expression in astrocytes and parvalbumin neurons.

Hevin, also known as SPARC-like 1, is a member of the secreted protein acidic and rich in cysteine family of matricellular proteins, which has been implicated in neuronal migration and synaptogenesis during development. Unlike previously characterized matricellular proteins, hevin remains strongly expressed in the adult brain in both astrocytes and neurons, but its precise pattern of expression is unknown. The present study provides the first systematic description of hevin mRNA distribution in the adult mouse brain. Using isotopic in situ hybridization, we showed that hevin is strongly expressed in the cortex, hippocampus, basal ganglia complex, diverse thalamic nuclei and brainstem motor nuclei. To identify the cellular phenotype of hevin-expressing cells, we used double fluorescent in situ hybridization in mouse and human adult brains. In the mouse, hevin mRNA was found in the majority of astrocytes but also in specific neuronal populations. Hevin was expressed in almost all parvalbumin-positive projection neurons and local interneurons. In addition, hevin mRNA was found in: (1) subsets of other inhibitory GABAergic neuronal subtypes, including calbindin, cholecystokinin, neuropeptide Y, and somatostatin-positive neurons; (2) subsets of glutamatergic neurons, identified by the expression of the vesicular glutamate transporters VGLUT1 and VGLUT2; and (3) the majority of cholinergic neurons from motor nuclei. Hevin mRNA was absent from all monoaminergic neurons and cholinergic neurons of the ascending pathway. A similar cellular profile of expression was observed in human, with expression of hevin in parvalbumin interneurons and astrocytes in the cortex and caudate nucleus as well as in cortical glutamatergic neurons. Furthermore, hevin transcript was enriched in ribosomes of astrocytes and parvalbumin neurons providing a direct evidence of hevin mRNAs translation in these cell types. This study reveals the unique and complex expression profile of the matricellular protein hevin in the adult brain. This distribution is compatible with a role of hevin in astrocytic-mediated adult synaptic plasticity and in the regulation of network activity mediated by parvalbumin-expressing neurons.

Draft Genome Sequence of an Onion Basal Rot Isolate of Fusarium proliferatum.

Fusarium proliferatum is a component of the onion basal rot disease complex. We present an annotated F. proliferatum draft genome sequence, totaling 45.8 Mb in size, assembled into 597 contigs, with a predicted 15,418 genes. The genome contains 58 secondary metabolite clusters and homologs of the Fusarium oxysporum effector SIX2.

Tectono-metamorphic evolution of shallow crustal levels within active volcanic arcs. Insights from the exhumed Basal Complex of Basse-Terre (Guadeloupe, French West Indies)

In order to decipher the tectono-metamorphic evolution of shallow crustal levels of the active volcanic arc of the Guadeloupe archipelago (Lesser Antilles) we present new geochemical, geochronological, mineralogical and structural investigations of the so-called Basal Complex, the oldest and most eroded volcanic complex of Basse-Terre in Guadeloupe. Based on geochemical and mineralogical criteria we propose an updated geological map of this northern area of Basse-Terre. Using40Ar–39Ar geochronology we demonstrate first that the eroded “Gros Morne” of Deshaies belong to the Basal Complex, and second that this complex is characterized by 4.3 to 2 Ma old volcanism. Structural analysis reveals a long-lived deformation history with the development through time of N80-N100 schistose zones; N110-N140 and N160-N10 oriented hydrothermal breccias and N140-N150 brittle normal faults. The boundary between the Basal Complex and the southernmost Septentrional Chain corresponds to a series of faults with N 150° and N 50° main directions. Detailed mineralogical and petrological investigations, including thermodynamic modeling, allow the identification of three phases of post-magmatic mineralogical transformations with first a high-temperature stage under Greenschist to sub-Greenschist facies conditions (0.6–2 kbar for 250–300 °C), a re-equilibration under Zeolite facies conditions and finally a sub-surface alteration. The consistency between P–T conditions of metamorphism and the present day measured geothermal gradient demonstrates that the metamorphic pattern is the record of hydrothermal fluids circulation during building and cooling of the Lesser Antilles magmatic arc. The tectono-metamorphic evolution recognized in the Basal Complex enables us to propose a conceptual model for heat and fluid transport within shallow crustal levels of the Guadeloupe active volcanic arc.

Scribble and Discs-large direct initial assembly and positioning of adherens junctions during the establishment of apical-basal polarity.

Apical-basal polarity is a fundamental property of animal tissues. Drosophila embryos provide an outstanding model for defining mechanisms that initiate and maintain polarity. Polarity is initiated during cellularization, when cell-cell adherens junctions are positioned at the future boundary of apical and basolateral domains. Polarity maintenance then involves complementary and antagonistic interplay between apical and basal polarity complexes. The Scribble/Dlg module is well-known for promoting basolateral identity during polarity maintenance. Here, we report a surprising role for Scribble/Dlg in polarity initiation, placing it near the top of the network-positioning adherens junctions. Scribble and Dlg are enriched in nascent adherens junctions, are essential for adherens junction positioning and supermolecular assembly, and also play a role in basal junction assembly. We test the hypotheses for the underlying mechanisms, exploring potential effects on protein trafficking, cytoskeletal polarity or Par-1 localization/function. Our data suggest that the Scribble/Dlg module plays multiple roles in polarity initiation. Different domains of Scribble contribute to these distinct roles. Together, these data reveal novel roles for Scribble/Dlg as master scaffolds regulating assembly of distinct junctional complexes at different times and places.

A chemogenetic approach for treating experimental Parkinson's disease.

PD is a common neurodegenerative disease primarily affecting the cortico-basal ganglia loop. To investigate whether chemogenetic-mediated neuromodulation of various nuclei and pathways can counterbalance basal ganglia network abnormalities and improve motor disability in experimental PD. Experimental PD was induced by stereotactic injection of 6-OHDA to the medial forebrain bundle. Designer receptors exclusively activated by designer drugs were expressed in different basal ganglia nuclei by stereotactic injections of adeno-associated viral vectors. We compared motor performance, monitored by the open-field and rotarod tests, after random and blinded application of either normal saline or the synthetic receptor activator, clozapine-N-oxide. Motor performance, as measured by movement velocity, rotations, and rotarod scores, were significantly improved in PD mice by enhancing the activity of the GPe with Gq custom receptors and by reducing basal ganglia output activity, targeting the output nuclei GPi and SNr with Gi custom receptors. Our findings support the hypothesis that enhanced inhibitory output activity of the basal ganglia complex underlie motor signs in PD, and point to the therapeutic potential of chemogenetic based treatments in PD patients. © 2018 International Parkinson and Movement Disorder Society.

Basal Polarity Complex Scribble Is Required for Leukemic Initiation and Propagation through Negative Regulation of Apical Polarity Complex Activator Cdc42 and Hypoxia Inducing Factor-1α

Despite the introduction of tyrosine kinase inhibitor and CAR-T cell therapies, the prognosis for Ph+ and Ph-like acute lymphoblastic leukemia remains poor. In the present study, we show the role of the Scribble protein in both lymphoid and myeloid leukemogenesis. The polarity protein Scribble is a member of the basal polarity complex, which is down-regulated in many cancers, suggesting a possible tumor suppressor role, especially in so-called cancer initiating cells. Its effect and mechanisms of activity in leukemic cell fate along with its potential activity on leukemic initiating cells have only been recently started to elucidated. Using interferon-responsive inducible (Mx1-Cre) Scribble-deficient mice, we have characterized the role of Scribble in both retroviral transduction, transplantation animal models and binary, inducible stem cell initiated (Scl-tTA/TRE-BCR-ABL) serial propagation models of BCR-ABL induced leukemia. We found that Scribble expression is upregulated at both transcriptional and translational levels in p210- or p190-BCR-ABL induced leukemic progenitors. In vitro, leukemic colony formation was impaired in Scribble deficient leukemic progenitors (~48% reduction; p≤ 0.05, compared to Wt leukemic progenitors) demonstrating that Scribble is important for leukemogenesis. In vivo, the deletion of Scribble abrogates the development of myeloproliferative disease induced by p210-BCR-ABL (median survival: 70 vs 47 days in Scribble deficient and Wt chimeric mice, respectively; p≤0.05); and significantly impairs B-cell lymphoid leukemogenesis induced by p190-BCR-ABL (median survival: 80 vs 60 days for Scribble deficient and Wt chimeric animals, respectively). Mechanistically, BCR-ABL activates the apical polarity regulator Cdc42 in leukemic progenitors and this activation is inhibited by the deficiency of Scribble. The deficiency of Cdc42 does not impair leukemogenesis but the combined deficiency of Cdc42 and Scribble restores the in vivo survival (median survival: 47 days, p≤0.01 compared to Scribble deficient mice) in chimeric p190-BCR-ABL+ leukemic mice to levels similar to wild-type leukemic cells. These data indicate that Scribble-deficient leukemogenesis is dependent on oncogene induced Cdc42 activity in lymphoid progenitors. Furthermore, Scribble deficiency in leukemic progenitors increases the activation of the AMPK/mTORC1 signaling pathway and the protein expression and transcriptional activity of its downstream effector hypoxia-inducing factor-1α (HIF-1α). HIF-1α silencing by constitutive shRNA expression or inducible deletion in Scribble deleted B-lymphoid leukemic cells restored leukemic progenitor clonogenic efficiency (CFU average: 52 vs 110 per 1,000 B220+/EGFP+ BM cells, in Scribble and double Scribble/HIF-1α deficient, respectively; p≤0.01) and B-lymphoid leukemogenesis in vivo (median survival of 62 days; p≤0.05 compared with Scribble deficient chimeric animals). In addition, double deficiency of Scribble and HIF-1α restored AMPK/mTORC1 signaling to Wt leukemic levels. This data indicates that Scribble is a negative regulator of HIF-1α expression and activity, and the restoration of HIF-1α expression and activity to normal leukemic levels is necessary to restore leukemogenesis. Altogether, our data indicates that Scribble is a positive regulator of oncogenesis in leukemic progenitors, in vitro and in vivo, through Cdc42 and HIF-1α activities. DisclosuresNo relevant conflicts of interest to declare.

Architecture of the Southern Marginal Zone of the Upper Jurassic–Valanginian Carbonate Platform of the Northeastern Caucasus (Dagestan, Shakhdag Massif)

The structure of the southern marginal zone of the Upper Jurassic–Valanginian carbonate platform, Northeastern Caucasus, is considered with the Dagestan sector of the Shakhdag Massif as example. The massif consists of several large genetically diverse sedimentary complexes: (1) Upper Jurassic basal complex represented by the shallow-water terrigenous and carbonate sediments, which were formed under unstable sedimentation conditions; (2) reef complex ascribed to the barrier reef system; and (3) sedimentary sequence with the typical clinoform structure and the southwestward dip, toward the Dibrar trough. The formation of the marginal zone of the carbonate platform was mainly determined by (1) climatic conditions (transition from the humid climate in the Early and Middle Jurassic to the arid climate in the Late Jurassic) and (2) differences in the tectonic evolution of different structural-facies zones (weak subsidence of the Northeastern Caucasus, where carbonate platform was formed, and intense subsidence to the south in the flysch trough area). The formation of the internal structure of the Shakhdag Massif was mainly defined by the eustatic sea-level fluctuations.

The architecture of EGFR\u2019s basal complexes reveals autoinhibition mechanisms in dimers and oligomers

Our current understanding of epidermal growth factor receptor (EGFR) autoinhibition is based on X-ray structural data of monomer and dimer receptor fragments and does not explain how mutations achieve ligand-independent phosphorylation. Using a repertoire of imaging technologies and simulations we reveal an extracellular head-to-head interaction through which ligand-free receptor polymer chains of various lengths assemble. The architecture of the head-to-head interaction prevents kinase-mediated dimerisation. The latter, afforded by mutation or intracellular treatments, splits the autoinhibited head-to-head polymers to form stalk-to-stalk flexible non-extended dimers structurally coupled across the plasma membrane to active asymmetric tyrosine kinase dimers, and extended dimers coupled to inactive symmetric kinase dimers. Contrary to the previously proposed main autoinhibitory function of the inactive symmetric kinase dimer, our data suggest that only dysregulated species bear populations of symmetric and asymmetric kinase dimers that coexist in equilibrium at the plasma membrane under the modulation of the C-terminal domain.

Detrital signatures of impending collision: The deep-water record of the Upper Cretaceous Bordighera Sandstone and its basal complex (Ligurian Alps, Italy)

Despite intensive research efforts and significant advances in the understanding of subduction and obduction processes that affected several units which at the present day compose the Western Alps, the paleogeographic evolution of the Alpine Tethys represents a debated topic in Alpine geology. The role of the opposing continental margins (passive European margin and active Adriatic margin) as source regions for Cretaceous siliciclastic turbidites bordering the convergent system remains disputed. To address this question along the Ligurian Alps transect, a multi-proxy provenance analysis is applied to the two terrigenous superimposed units (Hauterivian-Campanian San Bartolomeo Fm. and Campanian-Maastrichtian Bordighera Sandstone) of the San Remo-Monte Saccarello Unit of the Western Ligurian Flysch complex. Petrographic analyses characterize the basal San Bartolomeo Fm. as quartz-rich mature sandstones. By contrast, the overlying Bordighera Sandstone represents texturally and compositionally immature first-cycle arkosic arenites. This change records the evolution of the sediment provenance from a stable craton into a continental basement uplift setting, reflecting erosion of granitoid plutons and the low-grade metamorphic basement. Geochronological data (UPb detrital zircon ages) indicate that virtually the same source terranes provided the source for both formations. The detrital age spectra display age peaks are compatible with well-documented magmatic and metamorphic pulses that affected the Southern Variscides in the Paleo-European margin. The strong affinity of clastic detritus with the Paleo-European margin basement rocks underlines the importance of the lower plate passive continental margin in supplying sand-rich turbidite systems prior to the arrival of the passive margin in the subduction zone.

Exosomal microRNA-29a mediates cardiac dysfunction and mitochondrial inactivity in obesity-related cardiomyopathy.

Present study aims to explore the pathophysiological role of microRNA (miR)-29a in the process of obesity-related cardiomyopathy in human subjects and mice. The expression level of circulating exosomal miR-29a was measured in 37 lean and 30 obese human subjects, and correlated with cardiac parameters. The effects of miR-29a on mitochondrial activity and cardiac function were investigated by treatment of miR-29a sponge in primary mouse cardiomyocytes and diet-induced obesity-related cardiomyopathy in mice. The increased circulating miR-29a level was closely associated with impaired human cardiac function, including ejection fraction (r = -0.2663, p < 0.05) and NT-proBNP levels (r = 0.4270, p < 0.001). Exosomes from obese human plasma mediated cardiomyocyte mitochondrial inactivity, but pre-treatment with miR-29a sponge attenuated the exosomal miR-29a-induced reduction of ATP production (p < 0.001), basal oxygen consumption (p < 0.01) and mitochondrial complex I activity (p < 0.01). In vivo mouse study, high fat diet damaged cardiac function, normal structure, and mitochondrial activity, whereas miR-29a sponge improved the cardiac status. Present study uncovered the correlation between circulating miR-29a and cardiac parameters in human subjects, and provided solid evidence of the therapeutic application of miR-29a sponge in combating obesity-mediated cardiac dysfunction.

Interaction Between an Active Pharmaceutical Ingredient Ionic Liquid Benzalkonium Salicylate and Small Biomolecules in Aqueous Solution: UV Absorption, Conductivity, and Volumetric Study

UV absorption spectroscopy, electrical conductivity and density experiments have been used to investigate the interactions of some small biomolecules (amino acids/dipeptides) with an active pharmaceutical ingredient in ionic liquid form (API-IL), benzalkonium salicylate (BaSal), in aqueous solution. A number of useful parameters, such as critical micellar concentration (cmc), aggregation number (Nagg) and limiting molar conductivity (Λ0) of BaSal, standard partial molar volumes (\(V_{2,\phi }^{ \circ }\)), corresponding volumes of transfer from water to aqueous BaSal solutions (ΔtrVo), standard partial molar expansibilities (\(E_{\phi }^{ \circ }\)), hydration number (nH) of small biomolecules, as well as the binding constants (Kb) for small biomolecule–BaSal complexes have been evaluated. The dependence of the properties on concentration, temperature and alkyl chain length of amino acids/dipeptides is examined. The results are used to identify the solute–solvent physicochemical interactions occurring in the studied systems.

Exosomal microRNA-194 causes cardiac injury and mitochondrial dysfunction in obese mice

Obesity is associated with increased cardiovascular morbidity and mortality, but the effects of circulating factors on cardiac function is not fully elucidated. Present study aims to explore the pathophysiological role of microRNA (miR)-194, one of hepatic enriched miRs, in the process of obesity-related cardiomyopathy in human subjects and mice. The expression level of circulating exosomal miR-194 was measured in 39 lean and 35 obese human subjects, and correlated with cardiac parameters. The effects of miR-194 on mitochondrial activity and cardiac function were investigated by administration of miR-194 sponge in mouse cardiomyocytes and obesity-related cardiomyopathy. The upregulation of circulating miR-194 level was closely correlated with impaired human cardiac function, including ejection fraction (r = −0.5002, p < 0.01) and NT-proBNP levels (r = 0.3670, p < 0.01). Exosomes from obese mice impaired myocyte mitochondrial activity, but blocking with miR-194 sponge attenuated the exosomal miR-194-induced reduction of ATP production (p < 0.05), basal oxygen consumption (p < 0.01) and mitochondrial complex I activity (p < 0.001). In vivo mouse study, high fat diet damaged cardiac function, normal structure and mitochondrial activity, whereas miR-194 sponge improved the cardiac status. Present study uncovered the correlation between circulating miR-194 and cardiac parameters in human subjects, and provided solid evidence of the therapeutic application of miR-194 sponge in combating obesity-mediated cardiac dysfunction.

Characterization of the two conformations adopted by the T3SS inner-membrane protein PrgK.

The pathogenic bacterium Salmonella enterica serovar Typhimurium utilizes two type III secretion systems (T3SS) to inject effector proteins into target cells upon infection. The T3SS secretion apparatus (the injectisome) is a large macromolecular assembly composed of over twenty proteins, many in highly oligomeric states. A sub-structure of the injectisome, termed the basal body, spans both membranes and the periplasmic space of the bacterium. It is primarily composed of three integral membranes proteins, InvG, PrgH, and PrgK, that form ring structures through which components are secreted. In particular, PrgK possesses a periplasmic region consisting of two globular domains joined by a linker polypeptide. We showed previously that in isolation, this region adopts two distinct conformations, of with only one is observed in the assembled basal body complex. Here, using NMR spectroscopy, we further characterize these two conformations. In particular, we demonstrate that the interaction of the linker region with the first globular domain, as found in the intact basal body, is dependent upon the cis conformation of the Leu77-Pro78 peptide. Furthermore, this interaction is pH-dependent due to coupling with hydrogen bond formation between Tyr75 and His42 in its neutral Nδ1 H tautomeric form. This pH-dependent interaction may play a role in the regulation of the secretion apparatus disassembly in the context of bacterial infection.

Regional geological setting of Guanajuato silver-gold deposits and quantitative petrophysical assessment of their hydrothermal alteration, Guanajuato, México

Geological setting of one of the world famous silver-gold deposits type is presented. The silver-gold vein system occurs in the southeastern portion of the Sierra de Guanajuato, which is a 100 km long, N45°W-trending mountain range in Central Mexico. The rocks exposed in the Sierra de Guanajuato and its surroundings can be divided into four broad stratigraphic successions: (1) the “Basal complex” which includes Mesozoic rocks and an early Eocene granitic batholith, (2) a thick (>1000 m) red bed sequence resting unconformably atop the basal complex, which was deposited in the lapse between 49 and 36 Ma, (3) a thick, faulted and tilted, Paleogene subaerial volcanic succession, and (4) Immediately north of Sierra de Guanajuato are exposed a widespread, flat-lying, sand and gravel deposits accumulated in a continental basin. These sediments contain fossil vertebrate faunas with ages between late Clarendonian and Blancan. Southeast of El Bajío fault system sand and gravel deposits, partially covered by basaltic andesites crop out. A similar relation between gravel deposits and mafic lava flows is seen at the top of Cerro El Cubilete, which is one of the highest point in Sierra de Guanajuato. Succession (1) experienced several shortening events during the Cretaceous and Paleocene, whereas successions (2) thru (4) were extended in several deformation pulses during the Cenozoic.Wall rock alteration changes in some petrophysical parameters were studied in the Veta Madre vein in the central part of the Guanajuato mining district. Hydrothermally altered rocks were characterized by their variations in the following petrophysical characteristics: (1) density, (2) effective porosity, (3) rapid volumetric saturation, and (4) constant saturation.Among the petrophysical characteristics was observed that is important for exploration at Guanajuato:1.The rock density tends to fall near the structures that present ore bodies at depth, and having little change when no hydrothermal alteration is present.2.The effective porosity (Pefec) of rocks suitable for mineralization increase their values.3.The rapid volumetric conditioned saturation (A) plays a big role when the hydrothermal fluids pass near the rocks with high values and produces mineralization.4.The constant saturation (1/B), their values tend to increase in areas with mineralization.Samples of host rocks collected above known spikes such as Las Torres and Sirena exhibit hydrothermal alteration with the following petrophysical characteristics: density tends to decrease whereas porosity, rapid volumetric and constant saturation increase. The use of these petrophysical parameters may be a low-cost technique to predict the presence of undiscovered orebodies in the Guanajuato mining district and elsewhere where similar mineralization occurs.