Mycofactocin is a putative, peptide derived, cofactor that is associated primarily with the Mycobacterium genera including the pathogen M. tuberculosis. The pathway consists of the three genes mftA, ...mftB, and mftC that encode for the peptide substrate, peptide chaperone, and a radical S‐adenosylmethionine protein (RS), respectively. Here, we show that the MftB acts as a peptide chaperone, binding MftA with a submicromolar KD (~ 100 nm) and MftC with a low micromolar KD (~ 2 μm). Moreover, we demonstrate that MftC is a radical S‐adenosylmethionine (SAM) enzyme. Finally, we show that MftC catalyzes the oxidative decarboxylation of the peptide MftA.
Read the Commentary on this article at doi: 10.1002/1873-3468.12281
The precise transcriptional regulation of gene expression is essential for vertebrate development, but the role of posttranscriptional regulatory mechanisms is less clear. Cytoplasmic RNA granules ...(RGs) function in the posttranscriptional control of gene expression, but the extent of RG involvement in organogenesis is unknown. We describe two human cases of pediatric cataract with loss-of-function mutations in TDRD7 and demonstrate that Tdrd7 nullizygosity in mouse causes cataracts, as well as glaucoma and an arrest in spermatogenesis. TDRD7 is a Tudor domain RNA binding protein that is expressed in lens fiber cells in distinct TDRD7-RGs that interact with STAU1-ribonucleoproteins (RNPs). TDRD7 coimmunoprecipitates with specific lens messenger RNAs (mRNAs) and is required for the posttranscriptional control of mRNAs that are critical to normal lens development and to RG function. These findings demonstrate a role for RGs in vertebrate organogenesis.
The risk factors determining the frequency of intrauterine transfusions (IUTs) for severely affected red blood cell alloimmunized singleton pregnancies are not well known.
To assess factors ...associated with IUT frequency and adverse pregnancy outcomes in transfused pregnancies.
Retrospective cohort analysis of 246 consecutive cases between 1991 and 2014. Time-to-event survival analysis for repeated events was used to evaluate risk of subsequent IUT. Multivariable logistic regression assessed odds of a composite adverse pregnancy outcome (intrauterine fetal death, termination of pregnancy, neonatal death, preterm birth <34 weeks' gestation).
Full information was available on232 cases (94.3%) and 716 IUTs. Fetal hydrops was associated with increased frequency (hazard ratio HR 1.29 95% CIs 1.15-1.47, p < 0.001) while higher fetal hemoglobin (Hb) pre-IUT (HR) 0.99 (95% CI 0.99-1.00, p = 0.021) and post-IUT (HR 0.99 95% CI 0.99-1.00 p = 0.042), and higher transfused blood volume (HR 0.98 95% CI 0.97-0.99 p < 0.001) were associated with reduced IUT frequency. Adverse pregnancy outcomes were more likely with lower gestational age (GA) at initial IUT. Antibody type was not associated with IUT frequency or adverse pregnancy outcomes.
Hydrops is associated with increased IUT frequency while lower GA at initial IUT is associated with higher adverse pregnancy outcomes in alloimmunized pregnancies.Higher transfused blood volumes, pre- and post-IUT Hb are associated with lower IUT frequency.
Glaucoma is a common ocular disorder that is a leading cause of blindness worldwide. It is characterized by the dysfunction and loss of retinal ganglion cells (RGCs). Although many studies have ...implicated various molecules in glaucoma, no mechanism has been shown to be responsible for the earliest detectable damage to RGCs and their axons in the optic nerve. Here, we show that the leukocyte transendothelial migration pathway is activated in the optic nerve head at the earliest stages of disease in an inherited mouse model of glaucoma. This resulted in proinflammatory monocytes entering the optic nerve prior to detectable neuronal damage. A 1-time x-ray treatment prevented monocyte entry and subsequent glaucomatous damage. A single x-ray treatment of an individual eye in young mice provided that eye with long-term protection from glaucoma but had no effect on the contralateral eye. Localized radiation treatment prevented detectable neuronal damage and dysfunction in treated eyes, despite the continued presence of other glaucomatous stresses and signaling pathways. Injection of endothelin-2, a damaging mediator produced by the monocytes, into irradiated eyes, combined with the other glaucomatous stresses, restored neural damage with a topography characteristic of glaucoma. Together, these data support a model of glaucomatous damage involving monocyte entry into the optic nerve.
Laquinimod (LAQ) is a new oral immunomodulatory compound that reduces relapse rate, brain atrophy and disability progression in multiple sclerosis (MS). LAQ has well-documented effects on ...inflammation in the periphery, but little is known about its direct activity within the central nervous system (CNS). To elucidate the impact of LAQ on CNS-intrinsic inflammation, we investigated the effects of LAQ on cuprizone-induced demyelination in mice in vivo and on primary CNS cells in vitro. Demyelination, inflammation, axonal damage and glial pathology were evaluated in LAQ-treated wild type and Rag-1-deficient mice after cuprizone challenge. Using primary cells we tested for effects of LAQ on oligodendroglial survival as well as on cytokine secretion and NF-κB activation in astrocytes and microglia. LAQ prevented cuprizone-induced demyelination, microglial activation, axonal transections, reactive gliosis and oligodendroglial apoptoses in wild type and Rag-1-deficient mice. LAQ significantly decreased pro-inflammatory factors in stimulated astrocytes, but not in microglia. Oligodendroglial survival was not affected by LAQ in vitro. Astrocytic, but not microglial, NF-κB activation was markedly reduced by LAQ as evidenced by NF-κB reporter assay. LAQ also significantly decreased astrocytic NF-κB activation in cuprizone-treated mice. Our data indicate that LAQ prevents cuprizone-induced demyelination by attenuating astrocytic NF-κB activation. These effects are CNS-intrinsic and not mediated by peripheral immune cells. Therefore, LAQ downregulation of the astrocytic pro-inflammatory response may be an important mechanism underlying its protective effects on myelin, oligodendrocytes and axons. Modulation of astrocyte activation may be an attractive therapeutic target to prevent tissue damage in MS.
Electron paramagnetic resonance (EPR) inversion recovery curves for vanadium catecholates and iron‑sulfur clusters were analyzed with three models: the sum of two exponentials, a stretched ...exponential, and a model-free distribution of exponentials (UPEN). For all data sets studied fits with a stretched exponential were statistically indistinguishable from the sum of two exponentials, and were significantly better than for single exponentials. UPEN provides insights into the structures of the distributions. For a vanadium(IV) tris catecholate the distribution of relaxation rates calculated with UPEN shows the contribution from spectral diffusion at low temperatures. The energy of the local mode for this complex, found from the temperature dependence of the spin lattice relaxation, is consistent with values expected for a metal-ligand vibration. For the 2Fe-2S+ cluster in pyruvate formate lyase activating enzyme (PFL-AE) the small stretched exponential β values (0.3) at low temperature and the distributions calculated with UPEN reflect the contribution from a second rapidly relaxing species that could be difficult to detect by continuous wave EPR. The distributions in 1/T1 for the 4Fe-4S+ clusters in Mycofactocin maturase were about a factor of four wider than for the three other systems studied. The very broad distribution of relaxation rates may be due to protein mobility and distributions in electronic energies and local environments for the clusters. UPEN provides insight into several situations that can result in low values of stretch parameter β including contributions from spectral diffusion, overlapping signals from distinguishable clusters, or very wide distributions.
Inversion recovery EPR data were analyzed by three methods: the sum of two exponentials (shown separately), two stretched exponential approaches, and a distribution. The temperature dependence of the T1 values permits analysis of the mechanism of relaxation and of temperatures regions in which more than one species or mechanism contributes. Display omitted
•EPR inversion recovery curves were analyzed to determine T1.•Models were stretched exponentials, sums of exponentials, or distributions.•Data for vanadium tris catecholate and three iron‑sulfur clusters were fitted.•Stretched exponentials or the sum of two exponentials were indistinguishable.•A distribution of exponentials provided insight into the stretched parameter β.
Filarial helminths infect approximately 120 million people worldwide initiating a type 2 immune response in the host. Influenza A viruses stimulate a virulent type 1 pro-inflammatory immune response ...that in some individuals can cause uncontrolled immunopathology and fatality. Although coinfection with filariasis and influenza is a common occurrence, the impact of filarial infection on respiratory viral infection is unknown. The aim of this study was to determine the impact of pre-existing filarial infection on concurrent infection with influenza A virus. A murine model of co-infection was established using the filarial helminth
and the H1N1 (A/WSN/33) influenza A virus (IAV). Co-infection was performed at 3 different stages of
infection (larval, juvenile adult, and patency), and the impact of co-infection was determined by IAV induced weight loss and clinical signs, quantification of viral titres, and helminth counts. Significant alterations of IAV pathogenesis, dependent upon stage of infection, was observed on co-infection with
. Larval stage
infection alleviated clinical signs of IAV co-infection, whilst more established juvenile adult infection also significantly delayed weight loss. Viral titres remained unaltered at either infection stage. In contrast, patent
infection led to a reversal of age-related resistance to IAV infection, significantly increasing weight loss and clinical signs of infection as well as increasing IAV titre. These data demonstrate that the progression of influenza infection can be ameliorated or worsened by pre-existing filarial infection, with the outcome dependent upon the stage of filarial infection.
We introduce Glaucoma Discovery Platform (GDP), an online environment for facile visualization and interrogation of complex transcription profiling datasets for glaucoma. We also report the ...availability of Datgan, the suite of scripts that was developed to construct GDP. This reusable software system complements existing repositories such as NCBI GEO or EBI ArrayExpress as it allows the construction of searchable databases to maximize understanding of user-selected transcription profiling datasets.
Datgan scripts were used to construct both the underlying data tables and the web interface that form GDP. GDP is populated using data from a mouse model of glaucoma. The data was generated using the DBA/2J strain, a widely used mouse model of glaucoma. The DBA/2J-Gpnmb+ strain provided a genetically matched control strain that does not develop glaucoma. We separately assessed both the retina and the optic nerve head, important tissues in glaucoma. We used hierarchical clustering to identify early molecular stages of glaucoma that could not be identified using morphological assessment of disease. GDP has two components. First, an interactive search and retrieve component provides the ability to assess gene(s) of interest in all identified stages of disease in both the retina and optic nerve head. The output is returned in graphical and tabular format with statistically significant differences highlighted for easy visual analysis. Second, a bulk download component allows lists of differentially expressed genes to be retrieved as a series of files compatible with Excel. To facilitate access to additional information available for genes of interest, GDP is linked to selected external resources including Mouse Genome Informatics and Online Medelian Inheritance in Man (OMIM).
Datgan-constructed databases allow user-friendly access to datasets that involve temporally ordered stages of disease or developmental stages. Datgan and GDP are available from http://glaucomadb.jax.org/glaucoma.
The antimalarial agent cladosporin is a nanomolar inhibitor of the Plasmodium falciparum lysyl‐tRNA synthetase, and exhibits activity against both blood‐ and liver‐stage infection. Cladosporin can be ...isolated from the fungus Cladosporium cladosporioides, where it is biosynthesized by a highly reducing (HR) and a non‐reducing (NR) iterative type I polyketide synthase (PKS) pair. Genome sequencing of the host organism and subsequent heterologous expression of these enzymes in Saccharomyces cerevisiae produced cladosporin, confirming the identity of the putative gene cluster. Incorporation of a pentaketide intermediate analogue indicated a 5+3 assembly by the HR PKS Cla2 and the NR PKS Cla3 during cladosporin biosynthesis. Advanced‐intermediate analogues were synthesized and incorporated by Cla3 to furnish new cladosporin analogues. A putative lysyl‐tRNA synthetase resistance gene was identified in the cladosporin gene cluster. Analysis of the active site emphasizes key structural features thought to be important in resistance to cladosporin.
The highly reducing and non‐reducing polyketide synthase pair that is responsible for the production of cladosporin in Cladosporium cladosporioides has been identified and heterologously expressed, and its functional activity has been demonstrated. A putative lysyl‐tRNA synthetase is also contained within the cladosporin gene cluster and proposed to be necessary for self‐resistance in the organism.
To investigate the involvement of different types of glutamate receptors in recognition memory, selective antagonists of NMDA and kainate receptors were locally infused into the perirhinal cortex of ...the rat temporal lobe. Such infusion of a selective kainate receptor antagonist produced an unusual pattern of recognition memory impairment: amnesia after a short (20 min) but not a long (24 h) delay. In contrast, antagonism of perirhinal NMDA glutamate receptors by locally infused AP-5 (2-amino-5-phosphonopentanoic acid) impaired recognition memory after the long but not the short delay. For both drugs, impairment was found when the drug was present during acquisition but not when it was present during retrieval. Experiments in vitro indicate that selective antagonism of NMDA receptors containing NR2A subunits blocks perirhinal long-term potentiation (LTP), whereas antagonism of NMDA receptors containing NR2B subunits blocks long-term depression (LTD). However, recognition memory after a 24 h delay was impaired only when both an NR2A and an NR2B antagonist were infused together, not when either was infused separately. These results establish that kainate receptors have a role in recognition memory that is distinct from that of NMDA receptors, that there must be at least two independent underlying memory mechanisms in the infused region, that this region and no other is necessary for both short-term and long-term familiarity discrimination, and that perirhinal-dependent long-term recognition memory does not rely solely on processes used in NMDA-dependent LTP or LTD (although it might be independently supported by components of each type of process with one substituting for the other).
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