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1.
Front Neurosci ; 17: 1289027, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38027498

RESUMO

Friedreich's ataxia (FRDA) is a severe multisystemic disorder caused by a deficiency of the mitochondrial protein frataxin. While some aspects of FRDA pathology are developmental, the causes underlying the steady progression are unclear. The inaccessibility of key affected tissues to sampling is a main hurdle. Skeletal muscle displays a disease phenotype and may be sampled in vivo to address open questions on FRDA pathophysiology. Thus, we performed a quantitative mass spectrometry-based proteomics analysis in gastrocnemius skeletal muscle biopsies from genetically confirmed FRDA patients (n = 5) and controls. Obtained data files were processed using Proteome Discoverer and searched by Sequest HT engine against a UniProt human reference proteome database. Comparing skeletal muscle proteomics profiles between FRDA and controls, we identified 228 significant differentially expressed (DE) proteins, of which 227 were downregulated in FRDA. Principal component analysis showed a clear separation between FRDA and control samples. Interactome analysis revealed clustering of DE proteins in oxidative phosphorylation, ribosomal elements, mitochondrial architecture control, and fission/fusion pathways. DE findings in the muscle-specific proteomics suggested a shift toward fast-twitching glycolytic fibers. Notably, most DE proteins (169/228, 74%) are target of the transcription factor nuclear factor-erythroid 2. Our data corroborate a mitochondrial biosignature of FRDA, which extends beyond a mere oxidative phosphorylation failure. Skeletal muscle proteomics highlighted a derangement of mitochondrial architecture and maintenance pathways and a likely adaptive metabolic shift of contractile proteins. The present findings are relevant for the design of future therapeutic strategies and highlight the value of skeletal muscle-omics as disease state readout in FRDA.

2.
bioRxiv ; 2023 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-37808638

RESUMO

Nirmatrelvir was the first protease inhibitor (PI) specifically developed against the SARS-CoV-2 main protease (3CLpro/Mpro) and licensed for clinical use. As SARS-CoV-2 continues to spread, variants resistant to nirmatrelvir and other currently available treatments are likely to arise. This study aimed to identify and characterize mutations that confer resistance to nirmatrelvir. To safely generate Mpro resistance mutations, we passaged a previously developed, chimeric vesicular stomatitis virus (VSV-Mpro) with increasing, yet suboptimal concentrations of nirmatrelvir. Using Wuhan-1 and Omicron Mpro variants, we selected a large set of mutants. Some mutations are frequently present in GISAID, suggesting their relevance in SARS-CoV-2. The resistance phenotype of a subset of mutations was characterized against clinically available PIs (nirmatrelvir and ensitrelvir) with cell-based and biochemical assays. Moreover, we showed the putative molecular mechanism of resistance based on in silico molecular modelling. These findings have implications on the development of future generation Mpro inhibitors, will help to understand SARS-CoV-2 protease-inhibitor-resistance mechanisms and show the relevance of specific mutations in the clinic, thereby informing treatment decisions.

3.
Hum Mol Genet ; 32(13): 2241-2250, 2023 06 19.
Artigo em Inglês | MEDLINE | ID: mdl-37027192

RESUMO

OBJECTIVE: In Friedreich's ataxia (FRDA), the most affected tissues are not accessible to sampling and available transcriptomic findings originate from blood-derived cells and animal models. Herein, we aimed at dissecting for the first time the pathophysiology of FRDA by means of RNA-sequencing in an affected tissue sampled in vivo. METHODS: Skeletal muscle biopsies were collected from seven FRDA patients before and after treatment with recombinant human Erythropoietin (rhuEPO) within a clinical trial. Total RNA extraction, 3'-mRNA library preparation and sequencing were performed according to standard procedures. We tested for differential gene expression with DESeq2 and performed gene set enrichment analysis with respect to control subjects. RESULTS: FRDA transcriptomes showed 1873 genes differentially expressed from controls. Two main signatures emerged: (1) a global downregulation of the mitochondrial transcriptome as well as of ribosome/translational machinery and (2) an upregulation of genes related to transcription and chromatin regulation, especially of repressor terms. Downregulation of the mitochondrial transcriptome was more profound than previously shown in other cellular systems. Furthermore, we observed in FRDA patients a marked upregulation of leptin, the master regulator of energy homeostasis. RhuEPO treatment further enhanced leptin expression. INTERPRETATION: Our findings reflect a double hit in the pathophysiology of FRDA: a transcriptional/translational issue and a profound mitochondrial failure downstream. Leptin upregulation in the skeletal muscle in FRDA may represent a compensatory mechanism of mitochondrial dysfunction, which is amenable to pharmacological boosting. Skeletal muscle transcriptomics is a valuable biomarker to monitor therapeutic interventions in FRDA.


Assuntos
Eritropoetina , Ataxia de Friedreich , Animais , Humanos , Transcriptoma/genética , Leptina/genética , Ataxia de Friedreich/patologia , Eritropoetina/genética , RNA , Músculo Esquelético/metabolismo , Proteínas de Ligação ao Ferro/genética , Proteínas de Ligação ao Ferro/metabolismo
4.
Electromagn Biol Med ; 41(4): 429-438, 2022 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-36189775

RESUMO

This work examines (a) the impact of electromagnetic fields (EMF) on heart rate variability (HRV), saliva cortisol, arterial blood oxygenation, and tympanic temperature, and (b) the potential effect of protective devices developed to counter EMF-induced stress. In a pilot study, recordings were taken during a 15-min mobile phone call emitting a high burden of EMF (electric, magnetic, high frequency) after a baseline measurement at rest with very low EMF. In a second visit, this was repeated with participants using three protective devices (insoles, pendant, mobile phone chip). In the main study, four experimental arms were employed, two of which replicated the experimental setup of the pilot study, and two of which examined the effect of only one mobile phone chip in an open-hidden-paradigm. In both experiments, exposure to EMF decreased HRV and increased salivary cortisol. In the protective experimental condition, HRV increased above and cortisol decreased below the level of the baseline measures. All differences were large and specific and not modulated by non-specific effects like placebo effects.


Assuntos
Telefone Celular , Telecomunicações , Humanos , Campos Eletromagnéticos/efeitos adversos , Hidrocortisona , Projetos Piloto , Exposição Ambiental , Ondas de Rádio
5.
Front Cardiovasc Med ; 9: 971869, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36093156

RESUMO

Cardiac MR thermometry shows promise for real-time guidance of radiofrequency ablation of cardiac arrhythmias. This technique uses ECG triggering, which can be unreliable in this situation. A prospective cardiac triggering method was developed for MR thermometry using the active tracking (AT) signal measured from catheter microcoils. In the proposed AT-based cardiac triggering (AT-trig) sequence, AT modules were repeatedly acquired to measure the catheter motion until a cardiac trigger was identified to start cardiac MR thermometry using single-shot echo-planar imaging. The AT signal was bandpass filtered to extract the motion induced by the beating heart, and cardiac triggers were defined as the extremum (peak or valley) of the filtered AT signal. AT-trig was evaluated in a beating heart phantom and in vivo in the left ventricle of a swine during temperature stability experiments (6 locations) and during one ablation. Stability was defined as the standard deviation over time. In the phantom, AT-trig enabled triggering of MR thermometry and resulted in higher temperature stability than an untriggered sequence. In all in vivo experiments, AT-trig intervals matched ECG-derived RR intervals. Mis-triggers were observed in 1/12 AT-trig stability experiments. Comparable stability of MR thermometry was achieved using peak AT-trig (1.0 ± 0.4°C), valley AT-trig (1.1 ± 0.5°C), and ECG triggering (0.9 ± 0.4°C). These experiments show that continuously acquired AT signal for prospective cardiac triggering is feasible. MR thermometry with AT-trig leads to comparable temperature stability as with conventional ECG triggering. AT-trig could serve as an alternative cardiac triggering strategy in situations where ECG triggering is not effective.

6.
N Biotechnol ; 71: 37-46, 2022 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-35926774

RESUMO

Fusion protein technologies improve the expression and purification of recombinant proteins, but the removal of the tags involved requires specific proteases. The circularly permuted caspase-2 (cpCasp2) with its specific cleavage site, efficiently generates the untagged protein. While cleavage with cpCasp2 is possible before all 20 proteinogenic amino acids, cleavage before valine, leucine, isoleucine, aspartate and glutamate suffers from slow, and before proline extremely slow, turnover. To make the platform fusion protein process even more general such that any protein with an authentic N-terminus can be produced with high efficiency, the bacterial selection system PROFICS (PRotease Optimization via Fusion-Inhibited Carbamoyltransferase-based Selection) was used to evolve cpCasp2 into a variant with a catalytic turnover two orders of magnitude higher and the ability to cleave before any amino acid. The high specificity and the stability of the original circularly permuted protease was fully retained in this mutant, while the high manufacturability was mostly retained, albeit with decreased soluble titer. Four point-mutations are responsible for this change in activity, two of which are located in or near the binding pocket of the active site. This variant was named CASPON enzyme and is a major component of the CASPase-based fusiON (CASPON) platform technology. Applicability for the production of recombinant proteins was demonstrated by enzymatic removal of the CASPON tag from five model proteins. The CASPON tag enables high soluble expressions, affinity purification and good accessibility for cleavage. The five industry-relevant proteins of interest were FGF2, TNF, GH, GCSF and PTH.


Assuntos
Aminoácidos , Caspase 2 , Cromatografia de Afinidade , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes
7.
Int J Mol Sci ; 23(14)2022 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-35887026

RESUMO

Fusion protein technologies to facilitate soluble expression, detection, or subsequent affinity purification in Escherichia coli are widely used but may also be associated with negative consequences. Although commonly employed solubility tags have a positive influence on titers, their large molecular mass inherently results in stochiometric losses of product yield. Furthermore, the introduction of affinity tags, especially the polyhistidine tag, has been associated with undesirable changes in expression levels. Fusion tags are also known to influence the functionality of the protein of interest due to conformational changes. Therefore, particularly for biopharmaceutical applications, the removal of the fusion tag is a requirement to ensure the safety and efficacy of the therapeutic protein. The design of suitable fusion tags enabling the efficient manufacturing of the recombinant protein remains a challenge. Here, we evaluated several N-terminal fusion tag combinations and their influence on product titer and cell growth to find an ideal design for a generic fusion tag. For enhancing soluble expression, a negatively charged peptide tag derived from the T7 bacteriophage was combined with affinity tags and a caspase-2 cleavage site applicable for CASPase-based fusiON (CASPON) platform technology. The effects of each combinatorial tag element were investigated in an integrated manner using human fibroblast growth factor 2 as a model protein in fed-batch lab-scale bioreactor cultivations. To confirm the generic applicability for manufacturing, seven additional pharmaceutically relevant proteins were produced using the best performing tag of this study, named CASPON-tag, and tag removal was demonstrated.


Assuntos
Escherichia coli , Fusão Gênica , Escherichia coli/genética , Escherichia coli/metabolismo , Humanos , Proteínas Recombinantes de Fusão/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Solubilidade
8.
Endocr Regul ; 55(4): 215-223, 2021 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-34879187

RESUMO

Objectives. The effectiveness of exogenously triggered serotonin (e.g., dietary supplements, drugs) increase is varied. However, since urinary serotonin concentrations were found to correlate with those in the cerebrospinal fluid, the olfactory system might be an efficient and testable pathway to quickly elevate serotonin levels due to its fast-acting central neurophysiological and peripheral pathways. However, little research has been devoted to investigate this assumption. This paper extends previous findings of parasympathetic activation of a specially designed essential oil inhaler (AromaStick® Balance) by experimentally testing its impact on urine serotonin and saliva cortisol excretion. Method. Two experiments involving healthy individuals were conducted to test the efficacy of essential oil application to the nose by employing different inhalation protocols and control conditions. Results. In the pilot study (n=8), serotonin urine excretion was increased after six inhalations (effect size Cohen's d=0.7). In the second experiment (n=80), inhalations proved superior to both the natural control condition and the pseudo placebo condition after three and six inhalation cycles (0.6

Assuntos
Hidrocortisona , Óleos Voláteis , Feminino , Humanos , Masculino , Óleos Voláteis/farmacologia , Projetos Piloto , Saliva , Serotonina
9.
J Biol Chem ; 297(4): 101095, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34418435

RESUMO

Proteases serve as important tools in biotechnology and as valuable drugs or drug targets. Efficient protein engineering methods to study and modulate protease properties are thus of great interest for a plethora of applications. We established PROFICS (PRotease Optimization via Fusion-Inhibited Carbamoyltransferase-based Selection), a bacterial selection system, which enables the optimization of proteases for biotechnology, therapeutics or diagnosis in a simple overnight process. During the PROFICS process, proteases are selected for their ability to specifically cut a tag from a reporter enzyme and leave a native N-terminus. Precise and efficient cleavage after the recognition sequence reverses the phenotype of an Escherichia coli knockout strain deficient in an essential enzyme of pyrimidine synthesis. A toolbox was generated to select for proteases with different preferences for P1' residues (the residue immediately following the cleavage site). The functionality of PROFICS is demonstrated with viral proteases and human caspase-2. PROFICS improved caspase-2 activity up to 25-fold after only one round of mutation and selection. Additionally, we found a significantly improved tolerance for all P1' residues caused by a mutation in a substrate interaction site. We showed that this improved activity enables cells containing the new variant to outgrow cells containing all other mutants, facilitating its straightforward selection. Apart from optimizing enzymatic activity and P1' tolerance, PROFICS can be used to reprogram specificities, erase off-target activity, optimize expression via tags/codon usage, or even to screen for potential drug-resistance-conferring mutations in therapeutic targets such as viral proteases in an unbiased manner.


Assuntos
Caspase 2 , Cisteína Endopeptidases , Evolução Molecular Direcionada , Escherichia coli , Engenharia de Proteínas , Caspase 2/biossíntese , Caspase 2/química , Caspase 2/genética , Cisteína Endopeptidases/biossíntese , Cisteína Endopeptidases/química , Cisteína Endopeptidases/genética , Escherichia coli/enzimologia , Escherichia coli/genética , Humanos
10.
Front Oncol ; 11: 660481, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33937075

RESUMO

The c-Myc protein (MYC) is a transcription factor with strong oncogenic potential controlling fundamental cellular processes. In most human tumors, MYC is overexpressed by enhanced transcriptional activation, gene amplification, chromosomal rearrangements, or increased protein stabilization. To pharmacologically suppress oncogenic MYC functions, multiple approaches have been applied either to inhibit transcriptional activation of the endogenous MYC gene, or to interfere with biochemical functions of aberrantly activated MYC. Other critical points of attack are targeted protein modification, or destabilization leading to a non-functional MYC oncoprotein. It has been claimed that the natural compound curcumin representing the principal curcumoid of turmeric (Curcuma longa) has anticancer properties although its specificity, efficacy, and the underlying molecular mechanisms have been controversially discussed. Here, we have tested curcumin's effect on MYC-dependent cell transformation and transcriptional activation, and found that this natural compound interferes with both of these MYC activities. Furthermore, in curcumin-treated cells, the endogenous 60-kDa MYC protein is covalently and specifically cross-linked to one of its transcriptional interaction partners, namely the 434-kDa transformation/transcription domain associated protein (TRRAP). Thereby, endogenous MYC levels are strongly reduced and cells stop to proliferate. TRRAP is a multidomain adaptor protein of the phosphoinositide 3-kinase-related kinases (PIKK) family and represents an important component of many histone acetyltransferase (HAT) complexes. TRRAP is important to mediate transcriptional activation executed by the MYC oncoprotein, but on the other hand TRRAP also negatively regulates protein stability of the tumor suppressor p53 (TP53). Curcumin-mediated covalent binding of MYC to TRRAP reduces the protein amounts of both interaction partners but does not downregulate TP53, so that the growth-arresting effect of wild type TP53 could prevail. Our results elucidate a molecular mechanism of curcumin action that specifically and irreversibly targets two crucial multifunctional cellular players. With regard to their broad impact in cancer, our findings contribute to explain the pleiotropic functions of curcumin, and suggest that this natural spice, or more bioavailable derivatives thereof, may constitute useful adjuvants in the therapy of MYC-dependent and TRRAP-associated human tumors.

11.
J Chem Inf Model ; 61(3): 1193-1203, 2021 03 22.
Artigo em Inglês | MEDLINE | ID: mdl-33570387

RESUMO

Rational-design methods have proven to be a valuable toolkit in the field of protein design. Numerical approaches such as free-energy calculations or QM/MM methods are fit to widen the understanding of a protein-sequence space but require large amounts of computational time and power. Here, we apply an efficient method for free-energy calculations that combines the one-step perturbation (OSP) with the third-power-fitting (TPF) approach. It is fit to calculate full free energies of binding from three different end states only. The nonpolar contribution to the free energies are calculated for a set of chosen amino acids from a single simulation of a judiciously chosen reference state. The electrostatic contributions, on the other hand, are predicted from simulations of the neutral and charged end states of the individual amino acids. We used this method to perform in silico saturation mutagenesis of two sites in human Caspase-2. We calculated relative binding free energies toward two different substrates that differ in their P1' site and in their affinity toward the unmutated protease. Although being approximate, our approach showed very good agreement upon validation against experimental data. 76% of the predicted relative free energies of amino acid mutations was found to be true positives or true negatives. We observed that this method is fit to discriminate amino acid mutations because the rate of false negatives is very low (<1.5%). The approach works better for a substrate with medium/low affinity with a Matthews correlation coefficient (MCC) of 0.63, whereas for a substrate with very low affinity, the MCC was 0.38. In all cases, the combined TPF + OSP approach outperformed the linear interaction energy method.


Assuntos
Caspases , Peptídeo Hidrolases , Simulação por Computador , Humanos , Mutagênese , Ligação Proteica , Termodinâmica
12.
Percept Mot Skills ; 128(1): 135-152, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33167760

RESUMO

Two recent publications demonstrated that specifically designed essential odor inhalers can enhance performance through (a) better selective attention and scanning speed and (b) physiological changes of increased heart rate variability and blood oxygenation. In this study, we compared two natural odor inhalers with a popular energy drink (Red Bull®) with regard to their ability to improve vigilance on a computerized attention test. We employed a four-armed, randomized controlled experimental design and used a modified version of the CompACT-Vi test module to investigate whether deep inhalations of essential oil scents improved vigilance. Both inhalers markedly improved the number of correctly identified targets and participants' reaction time when compared to a control condition and consumption of Red Bull® (0.9 < d < 1.3). Additionally, the number of correctly solved mathematical sums during the second half of the vigilance test was substantially higher (d = 1.3) with the use of inhalers than for the control and Red Bull participants. Inhaler use was also associated with relatively increased heart rate variability (d = 1.0) as a mechanism of adapting to the experimental demands. Thus, short and deep inhalations of essential oil scents delivered directly to the nose improved vigilance, while a popular energy drink failed to show an effect beyond that of a control group receiving no stimulant.


Assuntos
Odorantes , Projetos de Pesquisa , Cafeína , Cognição , Humanos , Nebulizadores e Vaporizadores
13.
Biomolecules ; 10(12)2020 11 24.
Artigo em Inglês | MEDLINE | ID: mdl-33255244

RESUMO

Caspase-2 is the most specific protease of all caspases and therefore highly suitable as tag removal enzyme creating an authentic N-terminus of overexpressed tagged proteins of interest. The wild type human caspase-2 is a dimer of heterodimers generated by autocatalytic processing which is required for its enzymatic activity. We designed a circularly permuted caspase-2 (cpCasp2) to overcome the drawback of complex recombinant expression, purification and activation, cpCasp2 was constitutively active and expressed as a single chain protein. A 22 amino acid solubility tag and an optimized fermentation strategy realized with a model-based control algorithm further improved expression in Escherichia coli and 5.3 g/L of cpCasp2 in soluble form were obtained. The generated protease cleaved peptide and protein substrates, regardless of N-terminal amino acid with high activity and specificity. Edman degradation confirmed the correct N-terminal amino acid after tag removal, using Ubiquitin-conjugating enzyme E2 L3 as model substrate. Moreover, the generated enzyme is highly stable at -20 °C for one year and can undergo 25 freeze/thaw cycles without loss of enzyme activity. The generated cpCasp2 possesses all biophysical and biochemical properties required for efficient and economic tag removal and is ready for a platform fusion protein process.


Assuntos
Caspase 2/biossíntese , Cisteína Endopeptidases/biossíntese , Escherichia coli/química , Proteínas Recombinantes de Fusão/biossíntese , Caspase 2/isolamento & purificação , Caspase 2/metabolismo , Clonagem Molecular , Cisteína Endopeptidases/isolamento & purificação , Cisteína Endopeptidases/metabolismo , Escherichia coli/metabolismo , Humanos , Proteínas Recombinantes de Fusão/isolamento & purificação , Proteínas Recombinantes de Fusão/metabolismo
14.
Proc Natl Acad Sci U S A ; 117(49): 31105-31113, 2020 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-33229534

RESUMO

Kinase-targeted therapies have the potential to improve the survival of patients with cancer. However, the cancer-specific spectrum of kinase alterations exhibits distinct functional properties and requires mutation-oriented drug treatments. Besides post-translational modifications and diverse intermolecular interactions of kinases, it is the distinct disease mutation which reshapes full-length kinase conformations, affecting their activity. Oncokinase mutation profiles differ between cancer types, as it was shown for BRAF in melanoma and non-small-cell lung cancers. Here, we present the target-oriented application of a kinase conformation (KinCon) reporter platform for live-cell measurements of autoinhibitory kinase activity states. The bioluminescence-based KinCon biosensor allows the tracking of conformation dynamics of full-length kinases in intact cells and real time. We show that the most frequent BRAF cancer mutations affect kinase conformations and thus the engagement and efficacy of V600E-specific BRAF inhibitors (BRAFi). We illustrate that the patient mutation harboring KinCon reporters display differences in the effectiveness of the three clinically approved BRAFi vemurafenib, encorafenib, and dabrafenib and the preclinical paradox breaker PLX8394. We confirmed KinCon-based drug efficacy predictions for BRAF mutations other than V600E in proliferation assays using patient-derived lung cancer cell lines and by analyzing downstream kinase signaling. The systematic implementation of such conformation reporters will allow to accelerate the decision process for the mutation-oriented RAF-kinase cancer therapy. Moreover, we illustrate that the presented kinase reporter concept can be extended to other kinases which harbor patient mutations. Overall, KinCon profiling provides additional mechanistic insights into full-length kinase functions by reporting protein-protein interaction (PPI)-dependent, mutation-specific, and drug-driven changes of kinase activity conformations.


Assuntos
Neoplasias Pulmonares/tratamento farmacológico , Conformação Proteica/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas B-raf/genética , Células A549 , Carbamatos/química , Carbamatos/farmacologia , Compostos Heterocíclicos com 2 Anéis/farmacologia , Humanos , Imidazóis/química , Imidazóis/farmacologia , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Mutação/efeitos dos fármacos , Oximas/química , Oximas/farmacologia , Fosfotransferases/antagonistas & inibidores , Fosfotransferases/ultraestrutura , Inibidores de Proteínas Quinases/química , Processamento de Proteína Pós-Traducional/efeitos dos fármacos , Processamento de Proteína Pós-Traducional/genética , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Proteínas Proto-Oncogênicas B-raf/ultraestrutura , Sulfonamidas/química , Sulfonamidas/farmacologia , Vemurafenib/química , Vemurafenib/farmacologia
15.
Proteins ; 88(10): 1303-1318, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32432825

RESUMO

The N-terminal cleavage of fusion tags to restore the native N-terminus of recombinant proteins is a challenging task and up to today, protocols need to be optimized for different proteins individually. Within this work, we present a novel protease that was designed in-silico to yield enhanced promiscuity toward different N-terminal amino acids. Two mutations in the active-site amino acids of human Caspase-2 were determined to increase the recognition of branched amino-acids, which show only poor binding capabilities in the unmutated protease. These mutations were determined by sequential and structural comparisons of Caspase-2 and Caspase-3 and their effect was additionally predicted using free-energy calculations. The two mutants proposed in the in-silico studies were expressed and in-vitro experiments confirmed the simulation results. Both mutants showed not only enhanced activities toward branched amino acids, but also smaller, unbranched amino acids. We believe that the created mutants constitute an important step toward generalized procedures to restore original N-termini of recombinant fusion proteins.


Assuntos
Aminoácidos de Cadeia Ramificada/química , Caspase 2/química , Caspase 3/química , Cisteína Endopeptidases/química , Mutação , Proteínas Recombinantes de Fusão/química , Sequência de Aminoácidos , Aminoácidos de Cadeia Ramificada/metabolismo , Caspase 2/genética , Caspase 2/metabolismo , Caspase 3/genética , Caspase 3/metabolismo , Domínio Catalítico , Clonagem Molecular , Cisteína Endopeptidases/genética , Cisteína Endopeptidases/metabolismo , Escherichia coli/genética , Escherichia coli/metabolismo , Expressão Gênica , Vetores Genéticos/química , Vetores Genéticos/metabolismo , Humanos , Cinética , Simulação de Dinâmica Molecular , Ligação Proteica , Conformação Proteica em alfa-Hélice , Conformação Proteica em Folha beta , Engenharia de Proteínas/métodos , Domínios e Motivos de Interação entre Proteínas , Proteólise , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Especificidade por Substrato , Termodinâmica
16.
IUBMB Life ; 72(6): 1168-1174, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32027084

RESUMO

The spectrum of kinase alterations displays distinct functional characteristics and requires kinase mutation-oriented strategies for therapeutic interference. Besides phosphotransferase activity, protein abundance, and intermolecular interactions, particular patient-mutations promote pathological kinase conformations. Despite major advances in identifying lead molecules targeting clinically relevant oncokinase functions, still many kinases are neglected and not part of drug discovery efforts. One explanation is attributed to challenges in tracking kinase activities. Chemical probes are needed to functionally annotate kinase functions, whose activities may not always depend on catalyzing phospho-transfer. Such non-catalytic kinase functions are related to transitions of full-length kinase conformations. Recent findings underline that cell-based reporter systems can be adapted to record conformation changes of kinases. Here, we discuss the possible applications of an extendable kinase conformation (KinCon) reporter toolbox for live-cell recording of kinase states. KinCon is a genetically encoded bioluminescence-based biosensor platform, which can be subjected for measurements of conformation dynamics of mutated kinases upon small molecule inhibitor exposure. We hypothesize that such biosensors can be utilized to delineate the molecular modus operandi for kinase and pseudokinase regulation. This should pave the path for full-length kinase-targeted drug discovery efforts aiming to identify single and combinatory kinase inhibitor therapies with increased specificity and efficacy.


Assuntos
Biologia Molecular/métodos , Proteínas Quinases/química , Proteínas Quinases/metabolismo , Técnicas Biossensoriais , Genes Reporter , Humanos , Luciferases/genética , Luciferases/metabolismo , Medições Luminescentes , Conformação Proteica , Proteínas Quinases/genética
17.
J Therm Biol ; 87: 102478, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31999606

RESUMO

BACKGROUND: A recent review article on an aromatherapeutic inhaler demonstrated clinical effects on a number of bodily systems, like the cardiovascular system, the respiratory system, the nervous system and the endocrine system. OBJECTIVE: This paper extends these findings and investigates whether specially designed essential oils inhalers are capable to counter experimentally induced stressful heat sensations. METHOD: Two prospective, randomized, controlled experiments using the Hot Immersion Test Paradigm (HIT) were conducted to investigate whether deep odor inhalations increase heat tolerance. RESULTS: In both experiments, the inhaler strongly prolonged pain tolerance and increased blood oxygenation (1 < d < 1.3). In the second experiment, the inhaler also increased heart rate variability (d = 1.3) as a mechanism to cope with heat stress. CONCLUSION: The ability to resist a stressful thermal stimulus can be exogenously improved by short and deep inhalations of essential scents directly delivered to the olfactory system.


Assuntos
Aromaterapia/métodos , Transtornos de Estresse por Calor/prevenção & controle , Óleos Voláteis/farmacologia , Termotolerância/efeitos dos fármacos , Administração por Inalação , Adulto , Feminino , Frequência Cardíaca , Transtornos de Estresse por Calor/terapia , Humanos , Imersão , Masculino , Pessoa de Meia-Idade , Nebulizadores e Vaporizadores , Óleos Voláteis/administração & dosagem , Oxigênio/sangue
18.
Physiother Theory Pract ; 36(1): 63-70, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29847188

RESUMO

Purpose: Although the exact prevalence of lipedema is unknown the number of women suffering from this condition is ever-growing. When treated conservatively, manual lymphatic drainage is regarded the gold standard. However, the rate of its effectiveness varies considerably with some women showing minimal to no improvement depending on severity of the disease and medical history. Methods: Thirty female patients diagnosed with lipedema stage 2-3 referred to physiotherapeutic treatment were randomly allocated to either six treatments of MLD or to six treatments of combined MLD and vibrotherapy treatment. Outcome parameters were the volume of lipedema at four locations of either the lower (n = 29) or the upper extremities (n = 1), as well as quality of life. Findings: A very large superiority of effectiveness was found for the combined treatment. Reduction of the sizes of lipedema varied between 1.1 < d < 3.2. These patients' quality of life was also considerably better (d = 1.0). Conclusions: Combining MLD with vibrotherapy treatment drastically enhances the effectiveness of treating lipedema.


Assuntos
Tratamento por Ondas de Choque Extracorpóreas/métodos , Lipedema/terapia , Drenagem Linfática Manual/métodos , Vibração , Adulto , Idoso , Feminino , Humanos , Pessoa de Meia-Idade , Ensaios Clínicos Pragmáticos como Assunto , Qualidade de Vida , Adulto Jovem
19.
Radiology ; 293(2): 384-393, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31573398

RESUMO

Background Commercial low-field-strength MRI systems are generally not equipped with state-of-the-art MRI hardware, and are not suitable for demanding imaging techniques. An MRI system was developed that combines low field strength (0.55 T) with high-performance imaging technology. Purpose To evaluate applications of a high-performance low-field-strength MRI system, specifically MRI-guided cardiovascular catheterizations with metallic devices, diagnostic imaging in high-susceptibility regions, and efficient image acquisition strategies. Materials and Methods A commercial 1.5-T MRI system was modified to operate at 0.55 T while maintaining high-performance hardware, shielded gradients (45 mT/m; 200 T/m/sec), and advanced imaging methods. MRI was performed between January 2018 and April 2019. T1, T2, and T2* were measured at 0.55 T; relaxivity of exogenous contrast agents was measured; and clinical applications advantageous at low field were evaluated. Results There were 83 0.55-T MRI examinations performed in study participants (45 women; mean age, 34 years ± 13). On average, T1 was 32% shorter, T2 was 26% longer, and T2* was 40% longer at 0.55 T compared with 1.5 T. Nine metallic interventional devices were found to be intrinsically safe at 0.55 T (<1°C heating) and MRI-guided right heart catheterization was performed in seven study participants with commercial metallic guidewires. Compared with 1.5 T, reduced image distortion was shown in lungs, upper airway, cranial sinuses, and intestines because of improved field homogeneity. Oxygen inhalation generated lung signal enhancement of 19% ± 11 (standard deviation) at 0.55 T compared with 7.6% ± 6.3 at 1.5 T (P = .02; five participants) because of the increased T1 relaxivity of oxygen (4.7e-4 mmHg-1sec-1). Efficient spiral image acquisitions were amenable to low field strength and generated increased signal-to-noise ratio compared with Cartesian acquisitions (P < .02). Representative imaging of the brain, spine, abdomen, and heart generated good image quality with this system. Conclusion This initial study suggests that high-performance low-field-strength MRI offers advantages for MRI-guided catheterizations with metal devices, MRI in high-susceptibility regions, and efficient imaging. © RSNA, 2019 Online supplemental material is available for this article. See also the editorial by Grist in this issue.


Assuntos
Cateterismo , Aumento da Imagem/instrumentação , Imageamento por Ressonância Magnética/instrumentação , Adulto , Artefatos , Cateterismo Cardíaco/instrumentação , Meios de Contraste , Desenho de Equipamento , Feminino , Humanos , Imagem por Ressonância Magnética Intervencionista/instrumentação , Metais , Razão Sinal-Ruído
20.
Europace ; 21(9): 1432-1441, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31219547

RESUMO

AIMS: Potential advantages of real-time magnetic resonance imaging (MRI)-guided electrophysiology (MR-EP) include contemporaneous three-dimensional substrate assessment at the time of intervention, improved procedural guidance, and ablation lesion assessment. We evaluated a novel real-time MR-EP system to perform endocardial voltage mapping and assessment of delayed conduction in a porcine ischaemia-reperfusion model. METHODS AND RESULTS: Sites of low voltage and slow conduction identified using the system were registered and compared to regions of late gadolinium enhancement (LGE) on MRI. The Sorensen-Dice similarity coefficient (DSC) between LGE scar maps and voltage maps was computed on a nodal basis. A total of 445 electrograms were recorded in sinus rhythm (range: 30-186) using the MR-EP system including 138 electrograms from LGE regions. Pacing captured at 103 sites; 47 (45.6%) sites had a stimulus-to-QRS (S-QRS) delay of ≥40 ms. Using conventional (0.5-1.5 mV) bipolar voltage thresholds, the sensitivity and specificity of voltage mapping using the MR-EP system to identify MR-derived LGE was 57% and 96%, respectively. Voltage mapping had a better predictive ability in detecting LGE compared to S-QRS measurements using this system (area under curve: 0.907 vs. 0.840). Using an electrical threshold of 1.5 mV to define abnormal myocardium, the total DSC, scar DSC, and normal myocardium DSC between voltage maps and LGE scar maps was 79.0 ± 6.0%, 35.0 ± 10.1%, and 90.4 ± 8.6%, respectively. CONCLUSION: Low-voltage zones and regions of delayed conduction determined using a real-time MR-EP system are moderately associated with LGE areas identified on MRI.


Assuntos
Doença do Sistema de Condução Cardíaco/diagnóstico por imagem , Doença do Sistema de Condução Cardíaco/fisiopatologia , Técnicas Eletrofisiológicas Cardíacas/métodos , Imagem por Ressonância Magnética Intervencionista/métodos , Traumatismo por Reperfusão Miocárdica/fisiopatologia , Taquicardia Ventricular/diagnóstico por imagem , Taquicardia Ventricular/fisiopatologia , Animais , Doença do Sistema de Condução Cardíaco/etiologia , Doença do Sistema de Condução Cardíaco/cirurgia , Ablação por Cateter , Modelos Animais de Doenças , Imageamento por Ressonância Magnética/métodos , Masculino , Traumatismo por Reperfusão Miocárdica/complicações , Traumatismo por Reperfusão Miocárdica/diagnóstico por imagem , Cirurgia Assistida por Computador , Sus scrofa , Suínos , Taquicardia Ventricular/etiologia , Taquicardia Ventricular/cirurgia
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