Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 31
Filtrar
1.
J Pharmacol Exp Ther ; 389(3): 313-314, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38772716

RESUMEN

We thank Dr. Weimer and her colleagues for their comments related to our recent work (Anding et al., 2023) and are grateful for the opportunity to further discuss the importance of efficient lysosomal targeting of enzyme-replacement therapies (ERT) for the treatment of Pompe disease. Patients with Pompe disease have mutations in the gene that encodes for acid α glucosidase (GAA), a lysosomal enzyme necessary for the breakdown of glycogen. The first-generation ERT, alglucosidase alfa, provides a lifesaving therapy for the severe form of the disease (infantile onset Pompe disease) and improves or stabilizes respiratory and motor function in patients with less severe disease (late onset Pompe disease). Despite these gains, significant unmet need remains, particularly in patients who display respiratory and motor decline following years of treatment. Poor tissue uptake and lysosomal targeting via inefficient binding of the cation-independent mannose-6-phosphate (M6P) receptor (CIMPR) in skeletal muscle contributed to this suboptimal treatment response, prompting the development of new ERTs with increased levels of M6P.


Asunto(s)
1-Desoxinojirimicina , Terapia de Reemplazo Enzimático , Enfermedad del Almacenamiento de Glucógeno Tipo II , Manosafosfatos , alfa-Glucosidasas , Enfermedad del Almacenamiento de Glucógeno Tipo II/tratamiento farmacológico , Animales , Terapia de Reemplazo Enzimático/métodos , Manosafosfatos/metabolismo , Ratones , alfa-Glucosidasas/uso terapéutico , alfa-Glucosidasas/metabolismo , alfa-Glucosidasas/administración & dosificación , 1-Desoxinojirimicina/análogos & derivados , 1-Desoxinojirimicina/administración & dosificación , 1-Desoxinojirimicina/uso terapéutico , Humanos , Lisosomas/efectos de los fármacos , Lisosomas/metabolismo
2.
J Pharmacol Exp Ther ; 387(2): 188-203, 2023 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-37679046

RESUMEN

Pompe disease is a rare glycogen storage disorder caused by a deficiency in the lysosomal enzyme acid α-glucosidase, which leads to muscle weakness, cardiac and respiratory failure, and early mortality. Alglucosidase alfa, a recombinant human acid α-glucosidase, was the first approved treatment of Pompe disease, but its uptake into skeletal muscle via the cation-independent mannose-6-phosphate (M6P) receptor (CIMPR) is limited. Avalglucosidase alfa has received marketing authorization in several countries for infantile-onset and/or late-onset Pompe disease. This recently approved enzyme replacement therapy (ERT) was glycoengineered to maximize CIMPR binding through high-affinity interactions with ∼7 bis-M6P moieties. Recently, small molecules like the glucosylceramide synthase inhibitor miglustat were reported to increase the stability of recombinant human acid α-glucosidase, and it was suggested that an increased serum half-life would result in better glycogen clearance. Here, the effects of miglustat on alglucosidase alfa and avalglucosidase alfa stability, activity, and efficacy in Pompe mice were evaluated. Although miglustat increased the stability of both enzymes in fluorescent protein thermal shift assays and when incubated in neutral pH buffer over time, it reduced their enzymatic activity by ∼50%. Improvement in tissue glycogen clearance and transcriptional dysregulation in Pompe mice correlated with M6P levels but not with miglustat coadministration. These results further substantiate the crucial role of CIMPR binding in lysosomal targeting of ERTs. SIGNIFICANCE STATEMENT: This work describes important new insights into the treatment of Pompe disease using currently approved enzyme replacement therapies (ERTs) coadministered with miglustat. Although miglustat increased the stability of ERTs in vitro, there was no positive impact to glycogen clearance and transcriptional correction in Pompe mice. However, increasing mannose-6-phosphate levels resulted in increased cell uptake in vitro and increased glycogen clearance and transcriptional correction in Pompe mice, further underscoring the crucial role of cation-independent mannose-6-phosphate receptor-mediated lysosomal targeting for ERTs.

3.
PLoS One ; 18(5): e0285198, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37130145

RESUMEN

Aquatic ecosystems are currently facing a multitude of stressors from anthropogenic impacts, including climate change, pollution, and overfishing. Public aquariums positively contribute to ecosystems through conservation, education, and scientific advancement; but may also negatively detract from these systems through collection of animals from the wild and sourcing from commercial suppliers. Changes within the industry have occurred, although evidence-based assessments of 1) how aquariums collect and maintain their populations to determine sustainability of the environment they have harvested; and 2) the welfare of these harvested animals once within the aquariums are still needed. The objectives of this study were to assess the ecosystem health of locations aquariums frequently visit to collect fish from the wild, and then evaluate the wellbeing of fishes at aquariums after extended periods in captivity. Assessments included use of chemical, physical, and biological indicators at field sites, and use of a quantitative welfare assessment at aquariums for comparison to species reared through aquaculture. Anthropogenic pressures at field sites were observed, but no evidence of high degradation or compromised health of animals were found. Welfare assessments of aquarium exhibit tanks produced high-positive scores overall (> 70/84), demonstrating that both wild collected (avg. score 78.8) and aquaculture fishes (avg. score 74.5) were coping appropriately within their environments. Although findings indicated that fish can be taken from the wild at low-moderate rates without any deleterious impact on the environment and cope equally well in aquarium settings, alternatives such as aquaculture should be considered as a strategy to reduce pressure on known stressed aquatic environments or where significant numbers of fishes are being taken.


Asunto(s)
Conservación de los Recursos Naturales , Ecosistema , Animales , Explotaciones Pesqueras , Peces , Acuicultura
4.
Mol Genet Metab ; 138(3): 107526, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36774918

RESUMEN

Pompe disease is a rare lysosomal storage disorder arising from recessive mutations in the acid α-glucosidase gene and resulting in the accumulation of glycogen, particularly in the cardiac and skeletal muscle. The current standard of care is administration of enzyme replacement therapy in the form of alglucosidase alfa or the recently approved avalglucosidase alfa. In order to better understand the underlying cellular processes that are disrupted in Pompe disease, we conducted gene expression analysis on skeletal muscle biopsies obtained from late-onset Pompe disease patients (LOPD) prior to treatment and following six months of enzyme replacement with avalglucosidase alfa. The LOPD patients had a distinct transcriptomic signature as compared to control patient samples, largely characterized by perturbations in pathways involved in lysosomal function and energy metabolism. Although patients were highly heterogeneous, they collectively exhibited a strong trend towards attenuation of the dysregulated genes following just six months of treatment. Notably, the enzyme replacement therapy had a strong stabilizing effect on gene expression, with minimal worsening in genes that were initially dysregulated. Many of the cellular process that were altered in LOPD patients were also affected in the more clinically severe infantile-onset (IOPD) patients. Additionally, both LOPD and IOPD patients demonstrated enrichment across several inflammatory pathways, despite a lack of overt immune cell infiltration. This study provides further insight into Pompe disease biology and demonstrates the positive effects of avalglucosidase alfa treatment.


Asunto(s)
Enfermedad del Almacenamiento de Glucógeno Tipo II , Humanos , Enfermedad del Almacenamiento de Glucógeno Tipo II/tratamiento farmacológico , Transcriptoma , alfa-Glucosidasas/genética , alfa-Glucosidasas/uso terapéutico , Músculo Esquelético/patología , Perfilación de la Expresión Génica , Biopsia , Terapia de Reemplazo Enzimático/efectos adversos
5.
Mol Genet Metab ; 137(4): 328-341, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36334424

RESUMEN

Fabry disease (FD) is a rare lysosomal storage disorder, characterized by a reduction in α-galactosidase A enzyme activity and the progressive accumulation of globotriaosylceramide (GL3) and its metabolites in the cells of various organs. Agalsidase beta, an enzyme replacement therapy (ERT), is approved for use in patients with FD in Europe, Canada, Australia, South America, and Asia, and is the only ERT approved for use in the United States. In this review, we discuss the clinical relevance of GL3 accumulation, the effect of agalsidase beta on GL3 in target tissues, and the association between treatment-related tissue GL3 clearance and long-term structure, function, or clinical outcomes. Accumulation of GL3 in the kidney, heart, vasculature, neurons, skin, gastrointestinal tract and auditory system correlates to cellular damage and irreversible organ damage, as a result of sclerosis, fibrosis, apoptosis, inflammation, and endothelial dysfunction. Damage leads to renal dysfunction and end-stage renal disease; myocardial hypertrophy with heart failure and arrhythmias; ischemic stroke; neuropathic pain; skin lesions; intestinal ischemia and dysmotility; and hearing loss. Treatment with agalsidase beta is effective in substantially clearing GL3 in a range of cells from the tissues affected by FD. Agalsidase beta has also been shown to slow renal decline and lower the overall risk of clinical progression, demonstrating an indirect link between treatment-related GL3 clearance and stabilization of FD.


Asunto(s)
Enfermedad de Fabry , alfa-Galactosidasa , Humanos , alfa-Galactosidasa/uso terapéutico , Enfermedad de Fabry/patología , Relevancia Clínica , Terapia de Reemplazo Enzimático/efectos adversos , Proteínas Recombinantes/uso terapéutico
6.
PLoS One ; 17(6): e0268857, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35704642

RESUMEN

Factor quinolinone inhibitors (FQIs), a first-in-class set of small molecule inhibitors targeted to the transcription factor LSF (TFCP2), exhibit promising cancer chemotherapeutic properties. FQI1, the initial lead compound identified, unexpectedly induced a concentration-dependent delay in mitotic progression. Here, we show that FQI1 can rapidly and reversibly lead to mitotic arrest, even when added directly to mitotic cells, implying that FQI1-mediated mitotic defects are not transcriptionally based. Furthermore, treatment with FQIs resulted in a striking, concentration-dependent diminishment of spindle microtubules, accompanied by a concentration-dependent increase in multi-aster formation. Aberrant γ-tubulin localization was also observed. These phenotypes suggest that perturbation of spindle microtubules is the primary event leading to the mitotic delays upon FQI1 treatment. Previously, FQIs were shown to specifically inhibit not only LSF DNA-binding activity, which requires LSF oligomerization to tetramers, but also other specific LSF-protein interactions. Other transcription factors participate in mitosis through non-transcriptional means, and we recently reported that LSF directly binds α-tubulin and is present in purified cellular tubulin preparations. Consistent with a microtubule role for LSF, here we show that LSF enhanced the rate of tubulin polymerization in vitro, and FQI1 inhibited such polymerization. To probe whether the FQI1-mediated spindle abnormalities could result from inhibition of mitotic LSF-protein interactions, mass spectrometry was performed using as bait an inducible, tagged form of LSF that is biotinylated by endogenous enzymes. The global proteomics analysis yielded expected associations for a transcription factor, notably with RNA processing machinery, but also to nontranscriptional components. In particular, and consistent with spindle disruption due to FQI treatment, mitotic, FQI1-sensitive interactions were identified between the biotinylated LSF and microtubule-associated proteins that regulate spindle assembly, positioning, and dynamics, as well as centrosome-associated proteins. Probing the mitotic LSF interactome using small molecule inhibitors therefore supported a non-transcriptional role for LSF in mediating progression through mitosis.


Asunto(s)
Proteínas Asociadas a Microtúbulos , Quinolonas , Proteínas Asociadas a Microtúbulos/metabolismo , Microtúbulos/metabolismo , Mitosis , Quinolonas/metabolismo , Quinolonas/farmacología , Huso Acromático/metabolismo , Factores de Transcripción/metabolismo , Tubulina (Proteína)/metabolismo
7.
BioDrugs ; 35(4): 379-387, 2021 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-34143406

RESUMEN

The principles of comparability assessments have been accepted globally as offering sensitive and reliable tools with which to evaluate potential changes to biologics that may arise either through processing changes or through the creation of a copy (biosimilar) by a different sponsor. The comparability approach has evolved through systematic advances in four areas: clear and convergent guidelines for evaluation of potential changes to biologics; risk-based systems of weighting analytical data; progressive improvements in analytical methods; and advanced understanding of post-translational modifications. Routine regulatory expectations for clinical equivalence data are being reevaluated, as they seldom contribute to the assessment of similarity. Similarly, we show that requirements to compare biosimilars and locally sourced versions of their reference products are of questionable scientific value and represent a double standard by comparison with the invariable acceptance of the clinical profiles of novel biologics without reference to their sources. The consistent application of evidentiary standards for comparability to all biologics offers an opportunity for regulators to curtail their own assessments of new biosimilars and instead to recognize comparability assessments made in another jurisdiction (reliance), thereby gaining important efficiencies in the regulatory review of biosimilars and improving the competitiveness of the biosimilars market. Such consistency can also enhance the confidence of all stakeholders, especially patients and their providers, in all biologics.


Asunto(s)
Biosimilares Farmacéuticos , Aprobación de Drogas , Humanos , Procesamiento Proteico-Postraduccional
8.
J Dairy Sci ; 104(5): 6080-6095, 2021 May.
Artículo en Inglés | MEDLINE | ID: mdl-33663825

RESUMEN

Providing optimal calf care remains a challenge on many dairy farms and has important implications for the future health, welfare, and productivity of male and female calves. Recent research suggests that male dairy calves receive a lower quality of care early in life than female calves, but further investigation is required to determine the factors that influence this disparity. The objectives of this study were to understand dairy producer perspectives on neonatal calf care practices and explore differences between male and female calf care. Overall, 23 dairy producers in Ontario, Canada, participated in 4 focus groups about calf care practices that were recorded and evaluated qualitatively using thematic analysis. Major barriers for good calf care included lack of knowledge about the best management practices for calf care and the prioritization of farm resources toward the milking herd. Some producers also noted that farm infrastructure (particularly during challenging weather) and employee training were important limitations. The economic cost of providing good neonatal calf care was important primarily for male calves and acted as a motivation or a barrier depending on the producer's beliefs about calf care and how they chose to market their calves. The primary source of knowledge producers used to develop calf care practices was their own experience, although many also relied on dairy-industry advisors, most often veterinarians. Producers were motivated by social norms, along with intrinsic pride and obligation to provide good calf care, and these motives were influenced by their emotional state. Producers expressed beliefs about which aspects of calf care are most important-notably colostrum management-and appreciated simple and economical solutions to calf-rearing challenges. Calf care practices were varied, and we identified a diversity of knowledge, motivations, and barriers to adopting best management practices, which sometimes differed between male and female calves. Some producers said that they did not know what happened to their male calves after they left the farm and tended to prioritize the care of female over male calves in subtle ways, such as less timely provision of colostrum. The infrastructure investment and other costs associated with caring for male calves often limited their care, but producers were still motivated to provide adequate care for male calves. These findings represent potential targets for additional research and intervention strategies to improve calf care practices on dairy farms.


Asunto(s)
Bienestar del Animal , Industria Lechera , Animales , Animales Recién Nacidos , Bovinos , Calostro , Granjas , Femenino , Grupos Focales , Humanos , Masculino , Ontario , Embarazo
9.
Mol Cell ; 81(3): 426-441.e8, 2021 02 04.
Artículo en Inglés | MEDLINE | ID: mdl-33545059

RESUMEN

Eukaryotic genomes replicate via spatially and temporally regulated origin firing. Cyclin-dependent kinase (CDK) and Dbf4-dependent kinase (DDK) promote origin firing, whereas the S phase checkpoint limits firing to prevent nucleotide and RPA exhaustion. We used chemical genetics to interrogate human DDK with maximum precision, dissect its relationship with the S phase checkpoint, and identify DDK substrates. We show that DDK inhibition (DDKi) leads to graded suppression of origin firing and fork arrest. S phase checkpoint inhibition rescued origin firing in DDKi cells and DDK-depleted Xenopus egg extracts. DDKi also impairs RPA loading, nascent-strand protection, and fork restart. Via quantitative phosphoproteomics, we identify the BRCA1-associated (BRCA1-A) complex subunit MERIT40 and the cohesin accessory subunit PDS5B as DDK effectors in fork protection and restart. Phosphorylation neutralizes autoinhibition mediated by intrinsically disordered regions in both substrates. Our results reveal mechanisms through which DDK controls the duplication of large vertebrate genomes.


Asunto(s)
Replicación del ADN , Origen de Réplica , Proteínas Adaptadoras Transductoras de Señales/genética , Proteínas Adaptadoras Transductoras de Señales/metabolismo , Animales , Proteínas de la Ataxia Telangiectasia Mutada/genética , Proteínas de la Ataxia Telangiectasia Mutada/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1)/genética , Quinasa 1 Reguladora del Ciclo Celular (Checkpoint 1)/metabolismo , Replicación del ADN/efectos de los fármacos , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Femenino , Células HCT116 , Células HEK293 , Células HeLa , Humanos , Fosforilación , Inhibidores de Proteínas Quinasas/farmacología , Proteínas Serina-Treonina Quinasas/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Puntos de Control de la Fase S del Ciclo Celular , Especificidad por Sustrato , Factores de Tiempo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo , Xenopus laevis
10.
BMC Cancer ; 20(1): 552, 2020 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-32539694

RESUMEN

BACKGROUND: The oncogene LSF (encoded by TFCP2) has been proposed as a novel therapeutic target for multiple cancers. LSF overexpression in patient tumors correlates with poor prognosis in particular for both hepatocellular carcinoma and colorectal cancer. The limited treatment outcomes for these diseases and disappointing clinical results, in particular, for hepatocellular carcinoma in molecularly targeted therapies targeting cellular receptors and kinases, underscore the need for molecularly targeting novel mechanisms. LSF small molecule inhibitors, Factor Quinolinone Inhibitors (FQIs), have exhibited robust anti-tumor activity in multiple pre-clinical models, with no observable toxicity. METHODS: To understand how the LSF inhibitors impact cancer cell proliferation, we characterized the cellular phenotypes that result from loss of LSF activity. Cell proliferation and cell cycle progression were analyzed, using HeLa cells as a model cancer cell line responsive to FQI1. Cell cycle progression was studied either by time lapse microscopy or by bulk synchronization of cell populations to ensure accuracy in interpretation of the outcomes. In order to test for biological specificity of targeting LSF by FQI1, results were compared after treatment with either FQI1 or siRNA targeting LSF. RESULTS: Highly similar cellular phenotypes are observed upon treatments with FQI1 and siRNA targeting LSF. Along with similar effects on two cellular biomarkers, inhibition of LSF activity by either mechanism induced a strong delay or arrest prior to metaphase as cells progressed through mitosis, with condensed, but unaligned, chromosomes. This mitotic disruption in both cases resulted in improper cellular division leading to multiple outcomes: multi-nucleation, apoptosis, and cellular senescence. CONCLUSIONS: These data strongly support that cellular phenotypes observed upon FQI1 treatment are due specifically to the loss of LSF activity. Specific inhibition of LSF by either small molecules or siRNA results in severe mitotic defects, leading to cell death or senescence - consequences that are desirable in combating cancer. Taken together, these findings confirm that LSF is a promising target for cancer treatment. Furthermore, this study provides further support for developing FQIs or other LSF inhibitory strategies as treatment for LSF-related cancers with high unmet medical needs.


Asunto(s)
Benzodioxoles/farmacología , Proteínas de Unión al ADN/antagonistas & inhibidores , Neoplasias/tratamiento farmacológico , Quinolonas/farmacología , Factores de Transcripción/antagonistas & inhibidores , Apoptosis/efectos de los fármacos , Apoptosis/genética , Benzodioxoles/uso terapéutico , Puntos de Control del Ciclo Celular/efectos de los fármacos , Puntos de Control del Ciclo Celular/genética , División Celular/efectos de los fármacos , División Celular/genética , Senescencia Celular/efectos de los fármacos , Senescencia Celular/genética , Cromosomas Humanos/efectos de los fármacos , Cromosomas Humanos/genética , Cromosomas Humanos/metabolismo , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Ensayos de Selección de Medicamentos Antitumorales , Células HeLa , Humanos , Microscopía Intravital , Terapia Molecular Dirigida/métodos , Neoplasias/genética , Neoplasias/patología , Quinolonas/uso terapéutico , ARN Interferente Pequeño/metabolismo , Imagen de Lapso de Tiempo , Factores de Transcripción/genética , Factores de Transcripción/metabolismo
11.
Am J Lifestyle Med ; 14(1): 40-42, 2020.
Artículo en Inglés | MEDLINE | ID: mdl-31903079

RESUMEN

Advancing care delivery in lifestyle medicine and primary care has increasingly benefited from unique data sources and points. To remain competitive and relevant in modern practice, physicians and health systems must tackle and engage the implementation of big data and advanced applications for increasingly complex care. In many cases, information is being aggregated, though barriers exist in terms of accessing, interpreting, and making it actionable. New mobile device applications have eased some barriers, yet present challenges of their own. These new applications, designed to gather patient-entered data outside of traditional clinical settings, will require new policies, systems, and workflows. From a business perspective, collecting such data has potential value to patient care and patient engagement as well as financial incentives. If handled correctly, these additional data sources, including those not previously accessible, have the potential to vastly improve patient health.

12.
BioDrugs ; 33(5): 447-451, 2019 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-31388968

RESUMEN

The status of insulins in the USA is about to change as a regulatory matter. After 23 Mar 2020 they, and other hormone products previously regulated as drugs by the US Food and Drug Administration (FDA), even though biologics in science, will become biologics as a regulatory matter too and will be licensed under the Public Health Service Act. This has a number of ramifications for sponsors, patients, and their physicians.


Asunto(s)
Productos Biológicos , Aprobación de Drogas , Insulinas , Productos Biológicos/uso terapéutico , Diabetes Mellitus/tratamiento farmacológico , Etiquetado de Medicamentos , Humanos , Insulinas/uso terapéutico , Patient Protection and Affordable Care Act , Estados Unidos , United States Food and Drug Administration
13.
J Alzheimers Dis ; 69(2): 463-478, 2019.
Artículo en Inglés | MEDLINE | ID: mdl-31006686

RESUMEN

There is increasing evidence suggesting that amyloidogenic proteins might form deposits in non-neuronal tissues in neurodegenerative disorders such as Alzheimer's or Parkinson's diseases. However, the detection of these aggregation-prone proteins within the human skin has been controversial. Using immunohistochemistry (IHC) and mass spectrometry tissue imaging (MALDI-MSI), fresh frozen human skin samples were analyzed for the expression and localization of neurodegenerative disease-related proteins. While α-synuclein was detected throughout the epidermal layer of the auricular samples (IHC and MALDI-MSI), tau and Aß34 were also localized to the epidermal layer (IHC). In addition to Aß peptides of varying length (e.g., Aß40, Aß42, Aß34), we also were able to detect inflammatory markers within the same sample sets (e.g., thymosin ß-4, psoriasin). While previous literature has described α-synuclein in the nucleus of neurons (e.g., Parkinson's disease), our current detection of α-synuclein in the nucleus of skin cells is novel. Imaging of α-synuclein or tau revealed that their presence was similar between the young and old samples in our present study. Future work may reveal differences relevant for diagnosis between these proteins at the molecular level (e.g., age-dependent post-translational modifications). Our novel detection of Aß34 in human skin suggests that, just like in the brain, it may represent a stable intermediate of the Aß40 and Aß42 degradation pathway.


Asunto(s)
Péptidos beta-Amiloides/metabolismo , Epidermis/metabolismo , Mediadores de Inflamación/metabolismo , Enfermedades Neurodegenerativas/metabolismo , Fragmentos de Péptidos/metabolismo , alfa-Sinucleína/metabolismo , Proteínas tau/metabolismo , Anciano , Péptidos beta-Amiloides/análisis , Niño , Epidermis/química , Epidermis/patología , Femenino , Humanos , Mediadores de Inflamación/análisis , Masculino , Persona de Mediana Edad , Enfermedades Neurodegenerativas/patología , Fragmentos de Péptidos/análisis , Piel/química , Piel/metabolismo , Piel/patología , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodos , alfa-Sinucleína/análisis , Proteínas tau/análisis
15.
Acc Chem Res ; 51(5): 1220-1228, 2018 05 15.
Artículo en Inglés | MEDLINE | ID: mdl-29672021

RESUMEN

The prospect of recreating the complex structural hierarchy of protein folding in synthetic oligomers with backbones that are artificial in covalent structure ("foldamers") has long fascinated chemists. Foldamers offer complex functions from biostable scaffolds and have found widespread applications in fields from biomedical to materials science. Most precedent has focused on isolated secondary structures or their assemblies. In considering the goal of complex protein-like tertiary folding patterns, a key barrier became apparent. How does one design a backbone with covalent connectivity and a sequence of side-chain functional groups that will support defined intramolecular packing of multiple artificial secondary structures? Two developments were key to overcoming this challenge. First was the recognition of the power of blending α-amino acid residues with monomers differing in backbone connectivity to create "heterogeneous-backbone" foldamers. Second was the finding that replacing some of the natural α-residues in a biological sequence with artificial-backbone variants can result in a mimic that retains both the fold and function of the native sequence and, in some cases, gains advantageous characteristics. Taken together, these precedents lead to a view of a protein as chemical entity having two orthogonal sequences: a sequence of side-chain functional groups and a separate sequence of backbone units displaying those functional groups. In this Account, we describe our lab's work over the last ∼10 years to leverage the above concept of protein sequence duality in order to develop design principles for constructing heterogeneous-backbone foldamers that adopt complex protein-like tertiary folds. Fundamental to the approach is the utilization of a variety of artificial building blocks (e.g., d-α-residues, Cα-Me-α-residues, N-Me-α-residues, ß-residues, γ-residues, δ-residues, polymer segments) in concert, replacing a fraction of α-residues in a given prototype sequence. We provide an overview of the state-of-the-art in terms of design principles for choosing substitutions based on consideration of local secondary structure and retention of key side-chain functional groups. We survey high-resolution structures of backbone-modified proteins to illustrate how diverse artificial moieties are accommodated in tertiary fold contexts. We detail efforts to elucidate how backbone alteration impacts folding thermodynamics and describe how such data informs the development of improved design rules. Collectively, a growing body of results by our lab and others spanning multiple protein systems suggests there is a great deal of plasticity with respect to the backbone chemical structures upon which sequence-encoded tertiary folds can manifest. Moreover, these efforts suggest sequence-guided backbone alteration as a broadly applicable strategy for generating foldamers with complex tertiary folding patterns. We conclude by offering some perspective regarding the near future of this field, in terms of unanswered questions, technological needs, and opportunities for new areas of inquiry.


Asunto(s)
Proteínas Bacterianas/química , Materiales Biomiméticos/química , Secuencia de Aminoácidos , Aminoácidos/química , Cristalografía por Rayos X , Conformación Proteica en Hélice alfa , Conformación Proteica en Lámina beta , Dominios Proteicos , Estructura Terciaria de Proteína , Streptococcus/química , Dedos de Zinc
16.
J Am Chem Soc ; 139(23): 7931-7938, 2017 06 14.
Artículo en Inglés | MEDLINE | ID: mdl-28509549

RESUMEN

A variety of oligomeric backbones with compositions deviating from biomacromolecules can fold in defined ways. Termed "foldamers," these agents have diverse potential applications. A number of protein-inspired secondary structures (e.g., helices, sheets) have been produced from unnatural backbones, yet examples of tertiary folds combining several secondary structural elements in a single entity are rare. One promising strategy to address this challenge is the systematic backbone alteration of natural protein sequences, through which a subset of the native side chains is displayed on an unnatural building block to generate a heterogeneous backbone. A drawback to this approach is that substitution at more than one or two sites often comes at a significant energetic cost to fold stability. Here we report heterogeneous-backbone foldamers that mimic the zinc finger domain, a ubiquitous and biologically important metal-binding tertiary motif, and do so with a folded stability that is superior to the natural protein on which their design is based. A combination of UV-vis spectroscopy, isothermal titration calorimetry, and multidimensional NMR reveals that suitably designed oligomers with >20% modified backbones can form native-like tertiary folds with metal-binding environments identical to the prototype sequence (the third finger of specificity factor 1) and enhanced thermodynamic stability. These results expand the scope of heterogeneous-backbone foldamer design to a new tertiary structure class and show that judiciously applied backbone modification can be accompanied by improvement to fold stability.


Asunto(s)
Proteínas/química , Dedos de Zinc , Pliegue de Proteína , Estabilidad Proteica , Estructura Terciaria de Proteína , Termodinámica
17.
J Forensic Sci ; 60 Suppl 1: S108-15, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25088455

RESUMEN

This study explored the molecular mechanisms potentially underlying blow fly nocturnal oviposition. A behavioral study revealed that Calliphora vicina (Robineau-Desvoidy) (Diptera: Calliphoridae) possesses a diel rhythm of oviposition in light under 12:12 light/dark conditions. Reversal to 12:12 dark/light resulted in oviposition behavior changing to align with the adjusted regime in most females, but four of 59 experimental females lacked a diel rhythm of oviposition (were arrhythmic). Real-time PCR was used to monitor the molecular expression levels of known circadian genes per and tim in C. vicina to determine whether gene expression and behavior correlated. As with behavior, reversing light/dark conditions changed rhythmic gene expression to align with an adjusted light regime. This suggests that although it is unlikely that C. vicina will colonize dead bodies at night, arrhythmic females and oviposition in the dark was demonstrated.


Asunto(s)
Ritmo Circadiano/fisiología , Dípteros/fisiología , Expresión Génica , Oviposición/fisiología , Animales , Entomología , Femenino , Medicina Legal , Ovario/metabolismo , ARN Mensajero/metabolismo , ARN Ribosómico 28S/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa
18.
Rev. Soc. Bras. Med. Trop ; 47(6): 692-700, Nov-Dec/2014. tab
Artículo en Inglés | LILACS | ID: lil-732987

RESUMEN

Introduction We hypothesized that nutritional deficiency would be common in a cohort of postpartum, human immunodeficiency virus (HIV)-infected women and their infants. Methods Weight and height, as well as blood concentrations of retinol, α-tocopherol, ferritin, hemoglobin, and zinc, were measured in mothers after delivery and in their infants at birth and at 6-12 weeks and six months of age. Retinol and α-tocopherol levels were quantified by high performance liquid chromatography, and zinc levels were measured by atomic absorption spectrophotometry. The maternal body mass index during pregnancy was adjusted for gestational age (adjBMI). Results Among the 97 women 19.6% were underweight. Laboratory abnormalities were most frequently observed for the hemoglobin (46.4%), zinc (41.1%), retinol (12.5%) and ferritin (6.5%) levels. Five percent of the women had mean corpuscular hemoglobin concentrations < 31g/dL. The most common deficiency in the infants was α-tocopherol (81%) at birth; however, only 18.5% of infants had deficient levels at six months of age. Large percentages of infants had zinc (36.8%) and retinol (29.5%) deficiencies at birth; however, these percentages decreased to 17.5% and 18.5%, respectively, by six months of age. No associations between infant micronutrient deficiencies ...


Asunto(s)
Adulto , Femenino , Humanos , Lactante , Embarazo , Adulto Joven , Infecciones por VIH/sangre , Estado Nutricional , Periodo Posparto/sangre , Estudios de Cohortes , Ferritinas/sangre , Hemoglobinas/análisis , Hierro/sangre , Vitamina A/sangre , Zinc/sangre , alfa-Tocoferol/sangre
19.
Rev Soc Bras Med Trop ; 47(6): 692-700, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-25626647

RESUMEN

UNLABELLED: Introduction: We hypothesized that nutritional deficiency would be common in a cohort of postpartum, human immunodeficiency virus (HIV)-infected women and their infants. METHODS: Weight and height, as well as blood concentrations of retinol, α-tocopherol, ferritin, hemoglobin, and zinc, were measured in mothers after delivery and in their infants at birth and at 6-12 weeks and six months of age. Retinol and α-tocopherol levels were quantified by high performance liquid chromatography, and zinc levels were measured by atomic absorption spectrophotometry. The maternal body mass index during pregnancy was adjusted for gestational age (adjBMI). RESULTS: Among the 97 women 19.6% were underweight. Laboratory abnormalities were most frequently observed for the hemoglobin (46.4%), zinc (41.1%), retinol (12.5%) and ferritin (6.5%) levels. Five percent of the women had mean corpuscular hemoglobin concentrations < 31g/dL. The most common deficiency in the infants was α-tocopherol (81%) at birth; however, only 18.5% of infants had deficient levels at six months of age. Large percentages of infants had zinc (36.8%) and retinol (29.5%) deficiencies at birth; however, these percentages decreased to 17.5% and 18.5%, respectively, by six months of age. No associations between infant micronutrient deficiencies and either the maternal adjBMI category or maternal micronutrient deficiencies were found. CONCLUSIONS: Micronutrient deficiencies were common in HIV-infected women and their infants. Micronutrient deficiencies were less prevalent in the infants at six months of age. Neither underweight women nor their infants at birth were at increased risk for micronutrient deficiencies.


Asunto(s)
Infecciones por VIH/sangre , Estado Nutricional , Periodo Posparto/sangre , Adulto , Estudios de Cohortes , Femenino , Ferritinas/sangre , Hemoglobinas/análisis , Humanos , Lactante , Hierro/sangre , Embarazo , Vitamina A/sangre , Adulto Joven , Zinc/sangre , alfa-Tocoferol/sangre
20.
Forensic Sci Int ; 229(1-3): 100-7, 2013 Jun 10.
Artículo en Inglés | MEDLINE | ID: mdl-23683914

RESUMEN

The accuracy of minimum post-mortem interval (mPMI) estimates usually hinges upon the ability of forensic entomologists to predict the conditions under which calliphorids will colonise bodies. However, there can be delays between death and colonisation due to poorly understood abiotic and biotic factors, hence the need for a mPMI. To quantify the importance of various meteorological and light-level factors, beef liver baits were placed in the field (Victoria, Australia) on 88 randomly selected days over 3 years in all seasons and observed every 60-90 min for evidence of colonisation. Baits were exposed during daylight, and the following parameters were measured: barometric pressure, light intensity, wind speed, ambient temperature, relative humidity and rainfall. Collected data were analysed using backward LR logistic regression to produce an equation of colonisation probability. This type of analysis removes factors with the least influence on colonisation in successive steps until all remaining variables significantly increase the accuracy of predicting colonisation presence or absence. Ambient temperature was a positive predictor variable (an increase in temperature increased the probability of calliphorid colonisation). Relative humidity was a negative predictor variable (an increase in humidity decreased the probability of calliphorid colonisation). Barometric pressure, light intensity, wind speed and rainfall did not enhance the accuracy of the probability model; however, analysis of species activity patterns suggests that heavy rainfall and strong wind speeds inhibit calliphorid colonisation.


Asunto(s)
Presión Atmosférica , Dípteros , Conducta Alimentaria , Cambios Post Mortem , Tiempo (Meteorología) , Animales , Bovinos , Entomología , Patologia Forense , Modelos Logísticos
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...