scholarly journals The Contribution of Homocysteine Metabolism Disruption to Endothelial Dysfunction: State-of-the-Art

2019 ◽  
Vol 20 (4) ◽  
pp. 867 ◽  
Author(s):  
Ruben Esse ◽  
Madalena Barroso ◽  
Isabel Tavares de Almeida ◽  
Rita Castro
Keyword(s):  
Amino Acid ◽  
Endothelial Dysfunction ◽  
Molecular Basis ◽  
Methylation Status ◽  
Lipoprotein Metabolism ◽  
Negative Regulator ◽  
Vascular Lesions ◽  
Antioxidant Systems ◽  
Vascular Toxicity ◽  
The Impact

Homocysteine (Hcy) is a sulfur-containing non-proteinogenic amino acid formed during the metabolism of the essential amino acid methionine. Hcy is considered a risk factor for atherosclerosis and cardiovascular disease (CVD), but the molecular basis of these associations remains elusive. The impairment of endothelial function, a key initial event in the setting of atherosclerosis and CVD, is recurrently observed in hyperhomocysteinemia (HHcy). Various observations may explain the vascular toxicity associated with HHcy. For instance, Hcy interferes with the production of nitric oxide (NO), a gaseous master regulator of endothelial homeostasis. Moreover, Hcy deregulates the signaling pathways associated with another essential endothelial gasotransmitter: hydrogen sulfide. Hcy also mediates the loss of critical endothelial antioxidant systems and increases the intracellular concentration of reactive oxygen species (ROS) yielding oxidative stress. ROS disturb lipoprotein metabolism, contributing to the growth of atherosclerotic vascular lesions. Moreover, excess Hcy maybe be indirectly incorporated into proteins, a process referred to as protein N-homocysteinylation, inducing vascular damage. Lastly, cellular hypomethylation caused by build-up of S-adenosylhomocysteine (AdoHcy) also contributes to the molecular basis of Hcy-induced vascular toxicity, a mechanism that has merited our attention in particular. AdoHcy is the metabolic precursor of Hcy, which accumulates in the setting of HHcy and is a negative regulator of most cell methyltransferases. In this review, we examine the biosynthesis and catabolism of Hcy and critically revise recent findings linking disruption of this metabolism and endothelial dysfunction, emphasizing the impact of HHcy on endothelial cell methylation status.

scholarly journals Nuclear Import of Adenovirus DNA Involves Direct Interaction of Hexon with an N-Terminal Domain of the Nucleoporin Nup214

2014 ◽  
Vol 89 (3) ◽  
pp. 1719-1730 ◽  
Author(s):  
Aurélia Cassany ◽  
Jessica Ragues ◽  
Tinglu Guan ◽  
Dominique Bégu ◽  
Harald Wodrich ◽  
...  
Keyword(s):  
Amino Acid ◽  
Binding Site ◽  
Nuclear Import ◽  
Viral Genome ◽  
Molecular Basis ◽  
Nuclear Pore ◽  
Viral Dna ◽  
Terminal Domain ◽  
Cytoplasmic Face ◽  
The Impact

ABSTRACTIn this study, we characterized the molecular basis for binding of adenovirus (AdV) to the cytoplasmic face of the nuclear pore complex (NPC), a key step during delivery of the viral genome into the nucleus. We used RNA interference (RNAi) to deplete cells of either Nup214 or Nup358, the two major Phe-Gly (FG) repeat nucleoporins localized on the cytoplasmic side of the NPC, and evaluated the impact on hexon binding and AdV infection. The accumulation of purified hexon trimers or partially disassembled AdV at the nuclear envelope (NE) was observed in digitonin-permeabilized cells in the absence of cytosolic factors. Bothin vitrohexon binding andin vivonuclear import of the AdV genome were strongly reduced in Nup214-depleted cells but still occurred in Nup358-depleted cells, suggesting that Nup214 is a major binding site of AdV during infection. The expression of an NPC-targeted N-terminal domain of Nup214 in Nup214-depleted cells restored the binding of hexon at the NE and the nuclear import of protein VII (pVII), indicating that this region is sufficient to allow AdV binding. We further narrowed the binding site to a 137-amino-acid segment in the N-terminal domain of Nup214. Together, our results have identified a specific region within the N terminus of Nup214 that acts as a direct NPC binding site for AdV.IMPORTANCEAdVs, which have the largest genome of nonenveloped DNA viruses, are being extensively explored for use in gene therapy, especially in alternative treatments for cancers that are refractory to traditional therapies. In this study, we characterized the molecular basis for binding of AdV to the cytoplasmic face of the NPC, a key step for delivery of the viral genome into the nucleus. Our data indicate that a 137-amino-acid region of the nucleoporin Nup214 is a binding site for the major AdV capsid protein, hexon, and that this interaction is required for viral DNA import. These findings provide additional insight on how AdV exploits the nuclear transport machinery for infection. The results could promote the development of new strategies for gene transfer and enhance understanding of the nuclear import of other viral DNA genomes, such as those of papillomavirus or hepatitis B virus that induce specific cancers.

Abstract 126: Effects of Rosuvastatin on the Protein Composition of Lipoprotein Subfractions

2015 ◽  
Vol 35 (suppl_1) ◽  
Author(s):  
Scott M Gordon ◽  
Georgina Kemeh ◽  
Michael B Fessler ◽  
Alan T Remaley
Keyword(s):  
Lipoprotein Metabolism ◽  
Protein Composition ◽  
Protein Detection ◽  
Fold Increase ◽  
Cholesterol Content ◽  
Vascular Lesions ◽  
Lipid Lowering ◽  
Lipoprotein Subfractions ◽  
The Impact

Introduction: Statins, by inhibiting HMG-CoA reductase and up regulating hepatic LDL receptors, effectively lower plasma LDL-C by as much as 50%, thus reducing future CVD events. However, the physiological effects of statins are diverse and not all are related to lowering of LDL-C. Goal: The goal of this study was to test our hypothesis that some of these pleiotropic alternative effects from statins may be driven by compositional changes to lipoproteins distinct from their cholesterol content. We, therefore, performed a small clinical pilot study to assess the impact of statins on lipoprotein associated proteins in healthy individuals. Methods: Ten subjects with normal LDL-C (<130 mg/dL) were given rosuvastatin (20 mg/day) for 28 days. Plasma samples collected at baseline and after treatment were used for lipid measurement, nuclear magnetic resonance (NMR) lipoprotein profiling and lipoprotein proteomics. Results: The effects of rosuvastatin treatment on clinical lipid measures and NMR profile were consistent with established findings. Proteomic analysis of FPLC fractions representing LDL, HDL-1 (large) and HDL-2 (small) identified a total of 124 different proteins. Spectral counting was used to compare relative protein detection before and after statin therapy. Significant protein changes were found in each lipoprotein pool: LDL = 9, HDL-1 = 9 and HDL-2 = 4. These changes included both increases and decreases in proteins involved in lipoprotein metabolism, complement regulation and acute phase response. The most dramatic effect of the treatment was a profound increase in alpha-1-antirypsin (A1AT) spectral counts association with HDL-1 particles. Quantitative measurement by ELISA revealed an average 5.7 fold increase in HDL-1 associated A1AT. Preliminary in vitro studies indicate a potential functional role for A1AT enriched HDL in the formation of neutrophil extracellular traps (NETs), a pro-inflammatory component of vascular lesions. Summary: Based on these results, statins can significantly change the protein composition of both LDL and HDL. Some of these changes, such as the up regulation of A1AT on HDL, may convey anti-inflammatory functionality on lipoproteins and might contribute to some of the non-lipid lowering effects of statins.

scholarly journals Paramyxovirus V Protein Interaction with the Antiviral Sensor LGP2 Disrupts MDA5 Signaling Enhancement but Is Not Relevant to LGP2-Mediated RLR Signaling Inhibition

2014 ◽  
Vol 88 (14) ◽  
pp. 8180-8188 ◽  
Author(s):  
Kenny R. Rodriguez ◽  
Curt M. Horvath
Keyword(s):  
Amino Acid ◽  
Protein Interaction ◽  
Measles Virus ◽  
Negative Regulation ◽  
Negative Regulator ◽  
Amino Acid Substitutions ◽  
Helicase Domain ◽  
V Protein ◽  
Cellular Targets ◽  
The Impact

ABSTRACTThe interferon antiviral system is a primary barrier to virus replication triggered upon recognition of nonself RNAs by the cytoplasmic sensors encoded by retinoic acid-inducible gene I (RIG-I), melanoma differentiation-associated gene 5 (MDA5), and laboratory of genetics and physiology gene 2 (LGP2). Paramyxovirus V proteins are interferon antagonists that can selectively interact with MDA5 and LGP2 through contact with a discrete helicase domain region. Interaction with MDA5, an activator of antiviral signaling, disrupts interferon gene expression and antiviral responses. LGP2 has more diverse reported roles as both a coactivator of MDA5 and a negative regulator of both RIG-I and MDA5. This functional dichotomy, along with the concurrent interference with both cellular targets, has made it difficult to assess the unique consequences of V protein interaction with LGP2. To directly evaluate the impact of LGP2 interference, MDA5 and LGP2 variants unable to be recognized by measles virus and parainfluenza virus 5 (PIV5) V proteins were tested in signaling assays. Results indicate that interaction with LGP2 specifically prevents coactivation of MDA5 signaling and that LGP2's negative regulatory capacity was not affected. V proteins only partially antagonize RIG-I at high concentrations, and their expression had no additive effects on LGP2-mediated negative regulation. However, conversion of RIG-I to a direct V protein target was accomplished by only two amino acid substitutions that allowed both V protein interaction and efficient interference. These results clarify the unique consequences of MDA5 and LGP2 interference by paramyxovirus V proteins and help resolve the distinct roles of LGP2 in both activation and inhibition of antiviral signal transduction.IMPORTANCEParamyxovirus V proteins interact with two innate immune receptors, MDA5 and LGP2, but not RIG-I. V proteins prevent MDA5 from signaling to the beta interferon promoter, but the consequences of LGP2 targeting are poorly understood. As the V protein targets MDA5 and LGP2 simultaneously, and LGP2 is both a positive and negative regulator of both MDA5 and RIG-I, it has been difficult to evaluate the specific advantages conferred by LGP2 targeting. Experiments with V-insensitive proteins revealed that the primary outcome of LGP2 interference is suppression of its ability to synergize with MDA5. LGP2's negative regulation of MDA5 and RIG-I remains intact irrespective of V protein interaction. Complementary experiments demonstrate that RIG-I can be converted to V protein sensitivity by two amino acid substitutions. These findings clarify the functions of LGP2 as a positive regulator of MDA5 signaling, demonstrate the basis for V-mediated LGP2 targeting, and broaden our understanding of paramyxovirus-host interactions.

scholarly journals Hepatotoxicities Induced by Neoadjuvant Chemotherapy in Colorectal Cancer Liver Metastases: Distinguishing the True From the False

2019 ◽  
Vol 13 ◽  
pp. 117955491882545 ◽  
Author(s):  
Marie Desjardin ◽  
Benjamin Bonhomme ◽  
Brigitte Le Bail ◽  
Serge Evrard ◽  
Véronique Brouste ◽  
...  
Keyword(s):  
Vascular Lesions ◽  
First Line ◽  
Kappa Score ◽  
Colorectal Cancer Liver Metastases ◽  
Vascular Toxicity ◽  
Portal Vein Obstruction ◽  
Expert Pathologist ◽  
Apri Score ◽  
Male Sex ◽  
The Impact

Background: Pre-operative chemotherapy for colorectal liver metastasis (CRLM) is thought to be the cause of hepatotoxicity of non-tumoural parenchyma. Studies on hepatotoxicity are contradictory. We investigated the impact of a single-line pre-operative chemotherapy on non-tumoural liver analysed by an expert hepatico-pancreatico-biliary pathologist, and the consequences on surgical outcomes. Patients and methods: Patients operated for CRLM, after a pure first-line pre-operative chemotherapy, were retrospectively included. Two comparative histopathological analyses were performed for vascular toxicity and steatohepatitis. Results: Between 2003 and 2015, 147 patients were included. Chemotherapy was based on oxaliplatin (40.1%), irinotecan (55.8%), or both (4.1%). The expert pathologist described 38.8% of vascular lesions including dilation, nodular regeneration, and peliosis. In multivariate analysis, vascular lesions correlated to male sex ( P = .01), pre-operative platelets <150 g/L ( P = .04), and aspartate aminotransferase to platelet ratio index (APRI) score >0.36 ( P = .02). Steatohepatitis was observed in 15 patients (10.2%), more frequently after irinotecan (14.8% vs 3.4%, P = .01; odds ratio [OR] = 7.3; 95% confidence interval [CI] = [1.5-34.7]), and for patients with body mass index (BMI) >25 kg/m2 ( P = .004; OR = 10.0; 95% CI = [2.1-47.5]). A total of 29 patients (19.7%) developed major complications with 2 risk factors: portal vein obstruction (PVO) and septic surgery. Reproducibility assessment of steatohepatitis and dilated lesions by 2 pathologists showed moderate agreement (Kappa score 0.53 and 0.54, respectively). Conclusions: There is a probable association between non-alcoholic steatohepatitis (NASH) and irinotecan. Oxaliplatin seems to lead to higher vascular lesions. Except in the presence of pre-existent comorbidities, liver toxicities should not restrain the use of pre-operative chemotherapy prior to parenchymal-sparing surgery.

scholarly journals HLA-DRB1 Alleles Associated with Lower Leishmaniasis Susceptibility Share Common Amino Acid Polymorphisms and Epitope Binding Repertoires

Vaccines ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 270
Author(s):  
Nicky de Vrij ◽  
Pieter Meysman ◽  
Sofie Gielis ◽  
Wim Adriaensen ◽  
Kris Laukens ◽  
...  
Keyword(s):  
Amino Acid ◽  
Cell Epitope ◽  
Human Leukocyte ◽  
Leishmania Species ◽  
Hla Polymorphism ◽  
Common Amino Acid ◽  
Binding Core ◽  
Epitope Discovery ◽  
Epitope Binding ◽  
The Impact

Susceptibility for leishmaniasis is largely dependent on host genetic and immune factors. Despite the previously described association of human leukocyte antigen (HLA) gene cluster variants as genetic susceptibility factors for leishmaniasis, little is known regarding the mechanisms that underpin these associations. To better understand this underlying functionality, we first collected all known leishmaniasis-associated HLA variants in a thorough literature review. Next, we aligned and compared the protection- and risk-associated HLA-DRB1 allele sequences. This identified several amino acid polymorphisms that distinguish protection- from risk-associated HLA-DRB1 alleles. Subsequently, T cell epitope binding predictions were carried out across these alleles to map the impact of these polymorphisms on the epitope binding repertoires. For these predictions, we used epitopes derived from entire proteomes of multiple Leishmania species. Epitopes binding to protection-associated HLA-DRB1 alleles shared common binding core motifs, mapping to the identified HLA-DRB1 amino acid polymorphisms. These results strongly suggest that HLA polymorphism, resulting in differential antigen presentation, affects the association between HLA and leishmaniasis disease development. Finally, we established a valuable open-access resource of putative epitopes. A set of 14 HLA-unrestricted strong-binding epitopes, conserved across species, was prioritized for further epitope discovery in the search for novel subunit-based vaccines.

Assessing the Impact of Secondary Structure and Solvent Accessibility on Protein Evolution

Genetics ◽  
1998 ◽  
Vol 149 (1) ◽  
pp. 445-458 ◽  
Author(s):  
Nick Goldman ◽  
Jeffrey L Thorne ◽  
David T Jones
Keyword(s):  
Amino Acid ◽  
Secondary Structure ◽  
Protein Evolution ◽  
Solvent Accessibility ◽  
Strong Association ◽  
Length Distribution ◽  
Parametric Bootstrap ◽  
Amino Acid Replacement ◽  
Physical Constraints ◽  
The Impact

Abstract Empirically derived models of amino acid replacement are employed to study the association between various physical features of proteins and evolution. The strengths of these associations are statistically evaluated by applying the models of protein evolution to 11 diverse sets of protein sequences. Parametric bootstrap tests indicate that the solvent accessibility status of a site has a particularly strong association with the process of amino acid replacement that it experiences. Significant association between secondary structure environment and the amino acid replacement process is also observed. Careful description of the length distribution of secondary structure elements and of the organization of secondary structure and solvent accessibility along a protein did not always significantly improve the fit of the evolutionary models to the data sets that were analyzed. As indicated by the strength of the association of both solvent accessibility and secondary structure with amino acid replacement, the process of protein evolution—both above and below the species level—will not be well understood until the physical constraints that affect protein evolution are identified and characterized.

scholarly journals Bcl-2-dependent autophagy disruption during aging impairs amino acid utilization that is restored by hochuekkito

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Miwa Nahata ◽  
Sachiko Mogami ◽  
Hitomi Sekine ◽  
Seiichi Iizuka ◽  
Naoto Okubo ◽  
...  
Keyword(s):  
Amino Acid ◽  
Energy Homeostasis ◽  
Mitochondrial Dynamics ◽  
Negative Regulator ◽  
Aged Mice ◽  
Glucose Levels ◽  
Therapeutic Benefits ◽  
Age Related ◽  
Daily Food ◽  
Young Mice

AbstractChronic undernutrition contributes to the increase in frailty observed among elderly adults, which is a pressing issue in the sector of health care for older people worldwide. Autophagy, an intracellular recycling system, is closely associated with age-related pathologies. Therefore, decreased autophagy in aging could be involved in the disruption of energy homeostasis that occurs during undernutrition; however, the physiological mechanisms underlying this process remain unknown. Here, we showed that 70% daily food restriction (FR) induced fatal hypoglycemia in 23–26-month-old (aged) mice, which exhibited significantly lower hepatic autophagy than 9-week-old (young) mice. The liver expressions of Bcl-2, an autophagy-negative regulator, and Beclin1–Bcl-2 binding, were increased in aged mice compared with young mice. The autophagy inducer Tat-Beclin1 D11, not the mTOR inhibitor rapamycin, decreased the plasma levels of the glucogenic amino acid and restored the blood glucose levels in aged FR mice. Decreased liver gluconeogenesis, body temperature, physical activity, amino acid metabolism, and hepatic mitochondrial dynamics were observed in the aged FR mice. These changes were restored by treatment with hochuekkito that is a herbal formula containing several autophagy-activating ingredients. Our results indicate that Bcl-2 upregulation in the liver during the aging process disturbs autophagy activation, which increases the vulnerability to undernutrition. The promotion of liver autophagy may offer clinical therapeutic benefits to frail elderly patients.

scholarly journals Codon harmonization reduces amino acid misincorporation in bacterially expressed P. falciparum proteins and improves their immunogenicity

AMB Express ◽  
2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Neeraja Punde ◽  
Jennifer Kooken ◽  
Dagmar Leary ◽  
Patricia M. Legler ◽  
Evelina Angov
Keyword(s):  
Protein Structure ◽  
Amino Acid ◽  
Codon Usage ◽  
Dna Sequences ◽  
Structural Integrity ◽  
Host Cells ◽  
Loss Of Function ◽  
Species Specific ◽  
And Function ◽  
The Impact

Abstract Codon usage frequency influences protein structure and function. The frequency with which codons are used potentially impacts primary, secondary and tertiary protein structure. Poor expression, loss of function, insolubility, or truncation can result from species-specific differences in codon usage. “Codon harmonization” more closely aligns native codon usage frequencies with those of the expression host particularly within putative inter-domain segments where slower rates of translation may play a role in protein folding. Heterologous expression of Plasmodium falciparum genes in Escherichia coli has been a challenge due to their AT-rich codon bias and the highly repetitive DNA sequences. Here, codon harmonization was applied to the malarial antigen, CelTOS (Cell-traversal protein for ookinetes and sporozoites). CelTOS is a highly conserved P. falciparum protein involved in cellular traversal through mosquito and vertebrate host cells. It reversibly refolds after thermal denaturation making it a desirable malarial vaccine candidate. Protein expressed in E. coli from a codon harmonized sequence of P. falciparum CelTOS (CH-PfCelTOS) was compared with protein expressed from the native codon sequence (N-PfCelTOS) to assess the impact of codon usage on protein expression levels, solubility, yield, stability, structural integrity, recognition with CelTOS-specific mAbs and immunogenicity in mice. While the translated proteins were expected to be identical, the translated products produced from the codon-harmonized sequence differed in helical content and showed a smaller distribution of polypeptides in mass spectra indicating lower heterogeneity of the codon harmonized version and fewer amino acid misincorporations. Substitutions of hydrophobic-to-hydrophobic amino acid were observed more commonly than any other. CH-PfCelTOS induced significantly higher antibody levels compared with N-PfCelTOS; however, no significant differences in either IFN-γ or IL-4 cellular responses were detected between the two antigens.

scholarly journals Searching for signatures of positive selection in cytochrome b gene associated with subterranean lifestyle in fast-evolving arvicolines (Arvicolinae, Cricetidae, Rodentia)

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Olga V. Bondareva ◽  
Nadezhda A. Potapova ◽  
Kirill A. Konovalov ◽  
Tatyana V. Petrova ◽  
Natalia I. Abramson
Keyword(s):  
Amino Acid ◽  
Oxidative Phosphorylation ◽  
Adaptive Evolution ◽  
Complex Structure ◽  
Subterranean Rodents ◽  
Amino Acid Sequence Variation ◽  
Tertiary Protein Structure ◽  
Metabolic Performance ◽  
The Impact ◽  
Subterranean Species

Abstract Background Mitochondrial genes encode proteins involved in oxidative phosphorylation. Variations in lifestyle and ecological niche can be directly reflected in metabolic performance. Subterranean rodents represent a good model for testing hypotheses on adaptive evolution driven by important ecological shifts. Voles and lemmings of the subfamily Arvicolinae (Rodentia: Cricetidae) provide a good example for studies of adaptive radiation. This is the youngest group within the order Rodentia showing the fastest rates of diversification, including the transition to the subterranean lifestyle in several phylogenetically independent lineages. Results We evaluated the signatures of selection in the mitochondrial cytochrome b (cytB) gene in 62 Arvicolinae species characterized by either subterranean or surface-dwelling lifestyle by assessing amino acid sequence variation, exploring the functional consequences of the observed variation in the tertiary protein structure, and estimating selection pressure. Our analysis revealed that: (1) three of the convergent amino acid substitutions were found among phylogenetically distant subterranean species and (2) these substitutions may have an influence on the protein complex structure, (3) cytB showed an increased ω and evidence of relaxed selection in subterranean lineages, relative to non-subterranean, and (4) eight protein domains possess increased nonsynonymous substitutions ratio in subterranean species. Conclusions Our study provides insights into the adaptive evolution of the cytochrome b gene in the Arvicolinae subfamily and its potential implications in the molecular mechanism of adaptation. We present a framework for future characterizations of the impact of specific mutations on the function, physiology, and interactions of the mtDNA-encoded proteins involved in oxidative phosphorylation.

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