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1.
Cancer Immunol Res ; 2024 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-38885358

RESUMO

Interleukin-2 (IL-2) is a crucial cytokine in T-cell immunity and a promising combination partner to boost cancer vaccine efficacy. However, therapeutic application of IL-2 is hampered by its short half-life and substantial toxicities. Herein, we report preclinical characterization of a mouse serum albumin-IL-2 fusion protein (Alb-IL2) encoded on nucleoside-modified RNA delivered via a nanoparticle formulation (Alb-IL2 RNA-NP) mediating prolonged cytokine availability. Alb-IL2 RNA-NP was combined with RNA-lipoplex (RNA-LPX) vaccines to evaluate its effect on the expansion of vaccine-induced antigen-specific T-cell immunity. In mice dosed with Alb-IL2 RNA-NP, translated protein was shown to be systemically available up to two days, with an albumin-dependent preferred presence in the tumor and tumor-draining lymph node. Alb-IL2 RNA-NP administration prolonged serum availability of the cytokine compared to murine recombinant IL-2 (rIL-2). In combination with RNA-LPX vaccines, Alb-IL2 RNA-NP administration highly increased expansion of RNA-LPX vaccine-induced CD8+ T cells in the spleen and blood. The combination enhanced and sustained the fraction of IL-2 receptor (IL-2R)α-positive antigen-specific CD8+ T cells and ameliorated the functional capacity of the CD8+ T-cell population. Alb-IL2 RNA-NP strongly improved the antitumor activity and survival of concomitant RNA-LPX vaccination and PD-L1 blockade in a subcutaneous mouse tumor model. The favorable pharmacokinetic properties of Alb-IL2 RNA-NP render it an attractive modality for rationally designed combination immunotherapy. RNA vaccines that induce tumor-specific T-cell immunity for Alb-IL2 RNA-NP to further amplify are particularly attractive combination partners.

2.
Cancer Cell ; 42(4): 568-582.e11, 2024 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-38490213

RESUMO

Major histocompatibility complex (MHC) class I antigen presentation deficiency is a common cancer immune escape mechanism, but the mechanistic implications and potential strategies to address this challenge remain poorly understood. Studying ß2-microglobulin (B2M) deficient mouse tumor models, we find that MHC class I loss leads to a substantial immune desertification of the tumor microenvironment (TME) and broad resistance to immune-, chemo-, and radiotherapy. We show that treatment with long-lasting mRNA-encoded interleukin-2 (IL-2) restores an immune cell infiltrated, IFNγ-promoted, highly proinflammatory TME signature, and when combined with a tumor-targeting monoclonal antibody (mAB), can overcome therapeutic resistance. Unexpectedly, the effectiveness of this treatment is driven by IFNγ-releasing CD8+ T cells that recognize neoantigens cross-presented by TME-resident activated macrophages. These macrophages acquire augmented antigen presentation proficiency and other M1-phenotype-associated features under IL-2 treatment. Our findings highlight the importance of restoring neoantigen-specific immune responses in the treatment of cancers with MHC class I deficiencies.


Assuntos
Linfócitos T CD8-Positivos , Neoplasias , Animais , Camundongos , Antígenos de Histocompatibilidade Classe I/genética , Interleucina-2/genética , Interleucina-2/imunologia , Neoplasias/genética , RNA Mensageiro , Microambiente Tumoral
3.
mSphere ; 9(2): e0077123, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38319113

RESUMO

The bacteria within supragingival biofilms participate in complex exchanges with other microbes inhabiting the same niche. One example is the mutans group streptococci (Streptococcus mutans), implicated in the development of tooth decay, and other health-associated commensal streptococci species. Previously, our group transcriptomically characterized intermicrobial interactions between S. mutans and several species of oral bacteria. However, these experiments were carried out in a medium without human saliva. To better mimic their natural environment, we first evaluated how inclusion of saliva affected growth and biofilm formation of eight Streptococcus species individually and found saliva to positively benefit growth rates while negatively influencing biofilm biomass accumulation and altering spatial arrangement. These results carried over during evaluation of 29 saliva-derived isolates of various species. Surprisingly, we also found that addition of saliva increased the competitive behaviors of S. mutans in coculture competitions against commensal streptococci that led to increases in biofilm microcolony volumes. Through transcriptomically characterizing mono- and cocultures of S. mutans and Streptococcus oralis with and without saliva, we determined that each species developed a nutritional niche under mixed-species growth, with S. mutans upregulating carbohydrate uptake and utilization pathways while S. oralis upregulated genome features related to peptide uptake and glycan foraging. S. mutans also upregulated genes involved in oxidative stress tolerance, particularly manganese uptake, which we could artificially manipulate by supplementing in manganese leading to an advantage over its opponent. Our report highlights observable changes in microbial behaviors through leveraging environmental- and host-supplied resources over their competitors. IMPORTANCE: Dental caries (tooth decay) is the most prevalent disease for both children and adults nationwide. Caries are initiated from demineralization of the enamel due to organic acid production through the metabolic activity of oral bacteria growing in biofilm communities attached to the tooth's surface. Mutans group streptococci are closely associated with caries development and initiation of the cariogenic cycle, which decreases the amount of acid-sensitive, health-associated commensal bacteria while selecting for aciduric and acidogenic species that then further drives the disease process. Defining the exchanges that occur between mutans group streptococci and oral commensals in a condition that closely mimics their natural environment is of critical need toward identifying factors that can influence odontopathogen establishment, persistence, and outgrowth. The goal of our research is to develop strategies, potentially through manipulation of microbial interactions characterized here, that prevent the emergence of mutans group streptococci while keeping the protective flora intact.


Assuntos
Cárie Dentária , Saliva , Criança , Humanos , Saliva/microbiologia , Comportamento Competitivo , Manganês/metabolismo , Streptococcus/genética , Streptococcus mutans/genética , Streptococcus mutans/metabolismo , Biofilmes
4.
Anal Chem ; 96(5): 2199-2205, 2024 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-38179926

RESUMO

We present a new approach to Cu isotopic measurements using a state-of-the-art Nu Sapphire multicollector inductively coupled plasma source mass spectrometer equipped with a collision/reaction cell (CRC-MC-ICPMS). We investigate the effects of Na doping and Cu concentration mismatch between bracketing standard and unknown samples and demonstrate the efficacy of introducing a He-H2 gas mix into the CRC to efficiently eliminate the sample matrix-based 40Ar23Na+ isobaric interference on 63Cu+. This capability is crucial when measuring samples with high Na/Cu ratios, such as some biological samples, which have significantly different chemical compositions compared to most geological samples. Moreover, considering the necessity of obtaining large data sets for biological samples to ensure reliable interpretations, the implementation of a CRC for mitigating the 40Ar23Na+ interference offers the advantage of minimizing the requirement for extensive Cu chemical separation procedure prior to Cu isotopic measurements. Our results demonstrate that the accurate determination of the δ65Cu values is achievable for samples with Na/Cu concentration ratios of up to ∼65, even when measuring 100 ppb Cu solutions (equivalent to a signal of ∼3.5-4 V total Cu). Furthermore, our results showcase a good short-term repeatability on δ65Cu for pure Cu standard solutions (NIST SRM 976 and Cu-IPGP), typically of 0.05‰ (2 SD) when measuring >50 ppb Cu solutions. Our long-term external reproducibility stands at approximately 0.07‰ (2 SD). This value accounts for the variable Cu concentrations analyzed across the different analytical sequences (from 10 to 100 ppb Cu solutions). To validate the robustness of our analytical method, we first conduct a comparison between data sets from mice brains processed twice through column chemistry using a Thermo Finnigan Neptune MC-ICPMS and a Nu Sapphire CRC-MC-ICPMS in CRC mode. This comparison serves to verify the reliability of our method for measuring Cu isotopic composition using the CRC on samples with a low Na/Cu ratio after traditional chemical processing. Then, we compare the data sets obtained for biological standards (tuna fish ERM-CE 464 (IRMM) and human serum Seronorm Trace Elements Serum L-1) processed either once, or twice, through column chemistry and demonstrate that the CRC allows accurate Cu isotopic measurements of the samples processed only once and therefore with a higher Na/Cu ratio.


Assuntos
Cobre , Isótopos , Animais , Camundongos , Humanos , Reprodutibilidade dos Testes , Isótopos/química , Espectrometria de Massas/métodos , Análise Espectral
5.
Hum Vaccin Immunother ; 19(3): 2275457, 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-37968136

RESUMO

Chimeric antigen receptor T cell (CAR-T) therapy is an innovative immunotherapeutic approach that utilizes genetically modified T-cells to eliminate cancer cells using the specificity of a monoclonal antibody (mAb) coupled to the potent cytotoxicity of the T-lymphocyte. CAR-T therapy has yielded significant improvements in relapsed/refractory B-cell malignancies. Given these successes, CAR-T has quickly spread to other hematologic malignancies and is being increasingly explored in solid tumors. From early clinical applications to present day, CAR-T cell therapy has been accompanied by significant toxicities, namely cytokine release syndrome (CRS), immune effector cell-associated neurotoxicity syndrome (ICANS), and on-target off-tumor (OTOT) effects. While medical management has improved for CRS and ICANS, the ongoing threat of refractory symptoms and unanticipated idiosyncratic toxicities highlights the need for more powerful safety measures. This is particularly poignant as CAR T-cell therapy continues to expand into the solid tumor space, where the risk of unpredictable toxicities remains high. We will review CAR-T as an immunotherapeutic approach including emergence of unique toxicities throughout development. We will discuss known and novel strategies to mitigate these toxicities; additional safety challenges in the treatment of solid tumors, and how the inducible Caspase 9 "safety switch" provides an ideal platform for continued exploration.


Assuntos
Neoplasias , Receptores de Antígenos Quiméricos , Humanos , Imunoterapia Adotiva/efeitos adversos , Receptores de Antígenos Quiméricos/uso terapêutico , Anticorpos Monoclonais , Síndrome da Liberação de Citocina/terapia , Neoplasias/terapia
6.
Biomater Sci ; 11(22): 7229-7246, 2023 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-37791425

RESUMO

Fimbriae are long filamentous polymeric protein structures located upon the surface of bacteria. Often implicated in pathogenicity, the biosynthesis and function of fimbriae has been a productive topic of study for many decades. Evolutionary pressures have ensured that fimbriae possess unique structural and mechanical properties which are advantageous to bacteria. These properties are also difficult to engineer with well-known synthetic and natural fibres, and this has raised an intriguing question: can we exploit the unique properties of bacterial fimbriae in useful ways? Initial work has set out to explore this question by using Capsular antigen fragment 1 (Caf1), a fimbriae expressed naturally by Yersina pestis. These fibres have evolved to 'shield' the bacterium from the immune system of an infected host, and thus are rather bioinert in nature. Caf1 is, however, very amenable to structural mutagenesis which allows the incorporation of useful bioactive functions and the modulation of the fibre's mechanical properties. Its high-yielding recombinant synthesis also ensures plentiful quantities of polymer are available to drive development. These advantageous features make Caf1 an archetype for the development of new polymers and materials based upon bacterial fimbriae. Here, we cover recent advances in this new field, and look to future possibilities of this promising biopolymer.


Assuntos
Antígenos de Bactérias , Yersinia pestis , Antígenos de Bactérias/química , Antígenos de Bactérias/metabolismo , Proteínas de Bactérias/química , Fímbrias Bacterianas/metabolismo , Polímeros/química , Ciência dos Materiais , Yersinia pestis/química , Yersinia pestis/metabolismo
7.
bioRxiv ; 2023 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-37662325

RESUMO

The bacteria within supragingival biofilms participate in complex exchanges with other microbes inhabiting the same niche. One example are the mutans group streptococci (Streptococcus mutans), implicated in the development of tooth decay, and other health-associated commensal streptococci species. Previously, our group transcriptomically characterized intermicrobial interactions between S. mutans and several species of oral bacteria. However, these experiments were carried out in a medium that was absent of human saliva. To better mimic their natural environment, we first evaluated how inclusion of saliva affected growth and biofilm formation of eight streptococci species individually, and found saliva to positively benefit growth rates while negatively influencing biomass accumulation and altering spatial arrangement. These results carried over during evaluation of 29 saliva-derived isolates of various species. Surprisingly, we also found that addition of saliva increased the competitive behaviors of S. mutans in coculture competitions against commensal streptococci that led to increases in biofilm microcolony volumes. Through transcriptomically characterizing mono- and cocultures of S. mutans and Streptococcus oralis with and without saliva, we determined that each species developed a nutritional niche under mixed-species growth, with S. mutans upregulating carbohydrate uptake and utilization pathways while S. oralis upregulated genome features related to peptide uptake and glycan foraging. S. mutans also upregulated genes involved in oxidative stress tolerance, particularly manganese uptake, which we could artificially manipulate by supplementing in manganese to give it an advantage over its opponent. Our report highlights observable changes in microbial behaviors via leveraging environmental- and host-supplied resources over their competitors.

8.
Ann Neurol ; 93(3): 511-521, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-36401341

RESUMO

OBJECTIVES: Telemedicine is frequently used to provide remote neurological expertise for acute stroke workup and was associated with better functional outcomes when combined with a stroke unit system-of-care. We investigated whether such system-of-care yields additional benefits when implemented on top of neurological competence already available onsite. METHODS: Quality improvement measures were implemented within a "hub-and-spoke" teleneurology network in 11 hospitals already provided with onsite or telestroke expertise. Measures included dedicated units for neurological emergencies, standardization of procedures, multiprofessional training, and quality-of-care monitoring. Intervention effects were investigated in a controlled study enrolling patients insured at 3 participating statutory health insurances diagnosed with acute stroke or other neurological emergencies. Outcomes during the intervention period between November 2017 and February 2020 were compared with those pre-intervention between October 2014 and March 2017. To control for temporal trends, we compared outcomes of patients with respective diagnoses in 11 hospitals of the same region. Primary outcome was the composite of up-to-90-day death, new disability with the need of ambulatory or nursing home care, expressed by adjusted hazard ratio (aHR). RESULTS: We included 1,418 patients post-implementation (55% female, mean age 76.7 ± 12.8 year) and 2,306 patients pre-implementation (56%, 75.8 ± 13.0 year, respectively). The primary outcome occurred in 479/1,418 (33.8%) patients post-implementation and in 829/2,306 (35.9%) pre-implementation. The aHR for the primary outcome was 0.89 (95% confidence interval [CI]: 0.79-0.99, p = 0.04) with no improvement seen in non-participating hospitals between post- versus pre-implementation periods (aHR 1.04; 95% CI: 0.95-1.15). INTERPRETATION: Implementation of a multicomponent system-of-care was associated with a lower risk of poor outcomes. ANN NEUROL 2023;93:511-521.


Assuntos
Acidente Vascular Cerebral , Telemedicina , Humanos , Feminino , Pessoa de Meia-Idade , Idoso , Idoso de 80 Anos ou mais , Masculino , Emergências , Acidente Vascular Cerebral/diagnóstico , Projetos de Pesquisa
9.
Environ Sci Technol ; 57(1): 96-108, 2023 01 10.
Artigo em Inglês | MEDLINE | ID: mdl-36548159

RESUMO

We performed more than a year of mobile, 1 Hz measurements of lung-deposited surface area (LDSA, the surface area of 20-400 nm diameter particles, deposited in alveolar regions of lungs) and optically assessed fine particulate matter (PM2.5), black carbon (BC), and nitrogen dioxide (NO2) in central London. We spatially correlated these pollutants to two urban emission sources: major roadways and restaurants. We show that optical PM2.5 is an ineffective indicator of tailpipe emissions on major roadways, where we do observe statistically higher LDSA, BC, and NO2. Additionally, we find pollutant hot spots in commercial neighborhoods with more restaurants. A low LDSA (15 µm2 cm-3) occurs in areas with fewer major roadways and restaurants, while the highest LDSA (25 µm2 cm-3) occurs in areas with more of both sources. By isolating areas that are higher in one source than the other, we demonstrate the comparable impacts of traffic and restaurants on LDSA. Ratios of hyperlocal enhancements (ΔLDSA:ΔBC and ΔLDSA:ΔNO2) are higher in commercial neighborhoods than on major roadways, further demonstrating the influence of restaurant emissions on LDSA. We demonstrate the added value of using particle surface in identifying hyperlocal patterns of health-relevant PM components, especially in areas with strong vehicular emissions where the high LDSA does not translate to high PM2.5.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Ambientais , Material Particulado/análise , Poluentes Atmosféricos/análise , Dióxido de Nitrogênio/análise , Londres , Emissões de Veículos/análise , Pulmão , Monitoramento Ambiental , Poluição do Ar/análise
10.
Int J Mol Sci ; 23(23)2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36498931

RESUMO

In tissue engineering, the composition and the structural arrangement of molecular components within the extracellular matrix (ECM) determine the physical and biochemical features of a scaffold, which consequently modulate cell behavior and function. The microenvironment of the ECM plays a fundamental role in regulating angiogenesis. Numerous strategies in tissue engineering have attempted to control the spatial cues mimicking in vivo angiogenesis by using simplified systems. The aim of this study was to develop 3D porous crosslinked hydrogels with different spatial presentation of pro-angiogenic molecules to guide endothelial cell (EC) behavior. Hydrogels with pores and preformed microchannels were made with pharmaceutical-grade pullulan and dextran and functionalized with novel pro-angiogenic protein polymers (Caf1-YIGSR and Caf1-VEGF). Hydrogel functionalization was achieved by electrostatic interactions via incorporation of diethylaminoethyl (DEAE)-dextran. Spatial-controlled coating of hydrogels was realized through a combination of freeze-drying and physical absorption with Caf1 molecules. Cells in functionalized scaffolds survived, adhered, and proliferated over seven days. When incorporated alone, Caf1-YIGSR mainly induced cell adhesion and proliferation, whereas Caf1-VEGF promoted cell migration and sprouting. Most importantly, directed cell migration required the presence of both proteins in the microchannel and in the pores, highlighting the need for an adhesive substrate provided by Caf1-YIGSR for Caf1-VEGF to be effective. This study demonstrates the ability to guide EC behavior through spatial control of pro-angiogenic cues for the study of pro-angiogenic signals in 3D and to develop pro-angiogenic implantable materials.


Assuntos
Proteínas Angiogênicas , Fator A de Crescimento do Endotélio Vascular , Fator A de Crescimento do Endotélio Vascular/metabolismo , Proteínas Angiogênicas/metabolismo , Dextranos/farmacologia , Dextranos/metabolismo , Materiais Biocompatíveis/farmacologia , Hidrogéis/química , Células Endoteliais/metabolismo
11.
Macromol Biosci ; 22(9): e2200134, 2022 09.
Artigo em Inglês | MEDLINE | ID: mdl-35780498

RESUMO

There is a growing realization that 3D cell culture better mimics complex in vivo environments than 2D, lessening aberrant cellular behaviors and ultimately improving the outcomes of experiments. Chemically crosslinked hydrogels which imitate natural extracellular matrix (ECM) are proven cell culture platforms, but the encapsulation of cells within these hydrogel networks requires bioorthogonal crosslinking chemistries which can be cytotoxic, synthetically demanding, and costly. Capsular antigen fragment 1 (Caf1) is a bacterial, polymeric, fimbrial protein which can be genetically engineered to imitate ECM. Furthermore, it can, reversibly, thermally interconvert between its polymeric and monomeric forms even when chemically crosslinked within a hydrogel network. It is demonstrated that this meltable feature of Caf1 hydrogels can be utilized to encapsulate neonatal human dermal fibroblasts at a range of cell densities (2 × 105 -2 × 106  cells mL-1 of hydrogel) avoiding issues with chemical cytotoxicity. These hydrogels supported cell 3D culture for up to 21 d, successfully inducing cellular functions such as proliferation and migration. This work is significant because it further highlights the potential of simple, robust, Caf1-based hydrogels as a cell culture platform.


Assuntos
Técnicas de Cultura de Células , Hidrogéis , Matriz Extracelular , Humanos , Hidrogéis/farmacologia , Recém-Nascido , Polímeros
12.
PLoS Pathog ; 18(3): e1010447, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-35358289

RESUMO

The pathogenic bacterium Yersina pestis is protected from macrophage engulfment by a capsule like antigen, F1, formed of long polymers of the monomer protein, Caf1. However, despite the importance of this pathogen, the mechanism of protection was not understood. Here we demonstrate how F1 protects the bacteria from phagocytosis. First, we show that Escherichia coli expressing F1 showed greatly reduced adherence to macrophages. Furthermore, the few cells that did adhere remained on the macrophage surface and were not engulfed. We then inserted, by mutation, an "RGDS" integrin binding motif into Caf1. This did not change the number of cells adhering to macrophages but increased the fraction of adherent cells that were engulfed. Therefore, F1 protects in two separate ways, reducing cell adhesion, possibly by acting as a polymer brush, and hiding innate receptor binding sites needed for engulfment. F1 is very robust and we show that E. coli expressing weakened mutant polymers are engulfed like the RGDS mutant. This suggests that innate attachment sites on the native cell surface are exposed if F1 is weakened. Single-molecule force spectroscopy (SMFS) experiments revealed that wild-type F1 displays a very high mechanical stability of 400 pN. However, the mechanical resistance of the destabilised mutants, that were fully engulfed, was only 20% weaker. By only marginally exceeding the mechanical force applied to the Caf1 polymer during phagocytosis it may be that the exceptional tensile strength evolved to resist the forces applied at this stage of engulfment.


Assuntos
Peste , Yersinia pestis , Antígenos de Bactérias , Proteínas de Bactérias/genética , Escherichia coli/genética , Humanos , Polímeros , Yersinia pestis/genética
13.
Chem Res Toxicol ; 35(2): 203-217, 2022 02 21.
Artigo em Inglês | MEDLINE | ID: mdl-35124963

RESUMO

Abasic sites are common in cellular and synthetic DNA. As a result, it is important to characterize the chemical fate of these lesions. Amine-catalyzed strand cleavage at abasic sites in DNA is an important process in which conversion of small amounts of the ring-opened abasic aldehyde residue to an iminium ion facilitates ß-elimination of the 3'-phosphoryl group. This reaction generates a trans-α,ß-unsaturated iminium ion on the 3'-terminus of the strand break as an obligate intermediate. The canonical product expected from amine-catalyzed cleavage at an AP site is the corresponding trans-α,ß-unsaturated aldehyde sugar remnant resulting from hydrolysis of this iminium ion. Interestingly, a handful of studies have reported noncanonical 3'-sugar remnants generated by amine-catalyzed strand cleavage, but the formation and properties of these products are not well-understood. To address this knowledge gap, a nucleoside system was developed that enabled chemical characterization of the sugar remnants generated by amine-catalyzed ß-elimination in the 2-deoxyribose system. The results predict that amine-catalyzed strand cleavage at an AP site under physiological conditions has the potential to reversibly generate noncanonical cleavage products including cis-alkenal, 3-thio-2,3-dideoxyribose, and 2-deoxyribose groups alongside the canonical trans-alkenal residue on the 3'-terminus of the strand break. Thus, the model reactions provide evidence that the products generated by amine-catalyzed strand cleavage at abasic sites in cellular DNA may be more complex that commonly thought, with trans-α,ß-unsaturated iminium ion intermediates residing at the hub of interconverting product mixtures. The results expand the list of possible 3'-sugar remnants arising from amine-catalyzed cleavage of abasic sites in DNA that must be chemically or enzymatically removed for the completion of base excision repair and single-strand break repair in cells.


Assuntos
Aminas/química , Materiais Biomiméticos/química , DNA/efeitos dos fármacos , Desoxirribose/química , Nucleosídeos/química , Catálise , Dano ao DNA , Reparo do DNA , Conformação de Ácido Nucleico
15.
Eur Biophys J ; 50(3-4): 597-611, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33948690

RESUMO

Capsular antigen fragment 1 (Caf1) is an oligomeric protein consisting of 15 kDa monomeric subunits that are non-covalently linked through exceptionally strong and kinetically inert interactions into a linear polymer chain. It has been shown that after its thermal depolymerisation into unfolded monomeric subunits, Caf1 is able to efficiently repolymerise in vitro to reform its polymeric structure. However, little is known about the nature of the repolymerisation process. An improved understanding of this process will lead to the development of methods to better control the lengths of the repolymerised species, and ultimately, to better design of the properties of Caf1-based materials. Here we utilize small-angle X-ray scattering to estimate the size of Caf1 polymers during the first 24 h of the re-polymerisation process. Analytical ultracentrifugation measurements were also used to investigate the process post-24 h, where the rate of repolymerisation becomes considerably slower. Results show that in vitro polymerisation proceeds in a linear manner with no evidence observed for the formation of a lateral polymer network or uncontrolled aggregates. The rate of Caf1 in vitro repolymerisation was found to be concentration-dependent. Importantly, the rate of polymer growth was found to be relatively fast over the first few hours, before continuing at a dramatically slower rate. This observation is not consistent with the previously proposed step-growth mechanism of in vitro polymerisation of Caf1, where a linear increase in polymer length would be expected with time. We speculate how our observations may support the idea that the polymerisation process may be occurring at the ends of the chains with monomers adding sequentially. Our findings will contribute towards the development of new biomaterials for 3D cell culture and bio-printing.


Assuntos
Fímbrias Bacterianas , Materiais Biocompatíveis , Polímeros , Ultracentrifugação , Raios X
16.
Sensors (Basel) ; 21(5)2021 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-33668136

RESUMO

The growing demand for solutions related to measurement (e.g., digital sensors, smart meters, distributed measuring systems) imposes several concerns about information and process reliability. In this context, blockchain can play a crucial role as a platform to implement applications and activities in the context of legal metrology. In most countries, the National Metrology Institutes (NMIs) are responsible for promoting these initiatives. Thus, in this paper, we present a functional architecture to integrate NMIs in a collaborative blockchain network. We discuss the main aspects and features that an inter-NMI blockchain network must deliver. Furthermore, we implement our proposal using the Hyperledger Fabric platform. We connect peers from Physikalisch-Technische Bundesanstalt (PTB) (German NMI) and the National Institute of Metrology, Quality, and Technology (Inmetro) (Brazilian NMI) in a useful application that consists of a blockchain-based public-key infrastructure to identify and authenticate smart meters. Our preliminary results demonstrate that the proposed architecture meets the main requirements imposed by applications involving measurements. Furthermore, it opens the opportunity to integrate NMIs from other countries into the project, constituting an important global initiative in the metrology field.

17.
Biomater Sci ; 9(7): 2542-2552, 2021 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-33571331

RESUMO

Demand continues to grow for biomimetic materials able to create well-defined environments for modulating the behaviour of living cells in culture. Here, we describe hydrogels based upon the polymeric bacterial fimbriae protein capsular antigen fragment 1 (Caf1) that presents tunable biological properties for enhanced tissue cell culture applications. We demonstrate how Caf1 hydrogels can regulate cellular functions such as spreading, proliferation and matrix deposition of human dermal fibroblast cells (hDFBs). Caf1 hydrogels exploring a range of mechanical properties were prepared using copolymers featuring controlled compositions of inert wild-type Caf1 subunits and a mutant subunit displaying the RGDS peptide motif. The hydrogels showed excellent cytocompatibility with hDFBs and the ability to modulate both cell morphology and matrix deposition. Interestingly, Caf1 hydrogels displaying faster stress relaxation were demonstrated to show the highest metabolic activities of growing cells in comparison with other Caf1 hydrogel formulations. The stiffest Caf1 hydrogel impacted cellular morphology, inducing alignment of the cells. This work is significant as it clearly indicates that Caf1-based hydrogels offer tuneable biochemical and mechanical substrates conditions suitable for cell culture applications.


Assuntos
Materiais Biomiméticos , Hidrogéis , Técnicas de Cultura de Células , Fímbrias Bacterianas , Humanos , Polímeros
18.
Int J Cardiol ; 331: 46-56, 2021 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-33418002

RESUMO

BACKGROUND: Local administration of growth-inhibiting substances such as paclitaxel or sirolimus could reduce the risk of restenosis. In the drug coated balloon (DCB) technology the coating and the applied dose seem to play a major role. The aim of the present preclinical studies was to investigate the efficacy and safety of a specific DCB with paclitaxel as active ingredient and magnesium stearate as excipient. METHODS: Evaluation of the coating, drug release and transfer was done ex vivo and in vivo on peripheral arteries. A porcine coronary stent model was chosen to provoke intimal thickening. Conventional uncoated balloons were compared with paclitaxel urea and paclitaxel magnesium stearate coated balloons. QCA and histomorphometry was performed on treated vessels. Three areas of the heart were histologically examined for pathological changes. RESULTS: QCA and histomorphometry revealed no differences in baseline data between treatment groups. All DCB groups showed a significant reduction of angiographic and histologic parameters describing neointimal formation 4 weeks after treatment (e.g. mean angiographic late lumen loss all coated 0.31 ± 0.18 mm versus 0.91 ± 0.37 mm in the uncoated balloon group). There were no device-related animal deaths or clinical abnormalities. In spite of very slight-to-slight microscopic findings limited to small arterial vessels in downstream tissue there was no change in left ventricular ejection fraction or angiographic presentation of small side branches of treated arteries. CONCLUSION: Paclitaxel DCB using stearate as excipient show a high efficacy in reducing neointima formation after experimental coronary intervention. No evidence of myocardial damage resulting from distal embolization was found.


Assuntos
Fármacos Cardiovasculares , Reestenose Coronária , Animais , Catéteres , Materiais Revestidos Biocompatíveis , Reestenose Coronária/diagnóstico por imagem , Reestenose Coronária/prevenção & controle , Paclitaxel/efeitos adversos , Ácidos Esteáricos , Volume Sistólico , Suínos , Resultado do Tratamento , Função Ventricular Esquerda
19.
J Craniofac Surg ; 31(6): e586-e588, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32649534

RESUMO

Intradiploic hematomas are extremely rare, particularly in newborns. Caused by bleeding between the inner and outer tables of the calvarium, they manifest with bony swelling of the skull. The authors present the first case of an intraosseous hematoma associated with synostosis, and the first report in a female patient. The clinical, radiological, surgical, and pathological characteristics of this lesion are discussed.


Assuntos
Hematoma/cirurgia , Sinostose/cirurgia , Doenças Ósseas , Feminino , Hematoma/etiologia , Hematoma/patologia , Humanos , Recém-Nascido , Crânio/patologia , Sinostose/complicações , Sinostose/patologia
20.
ACS Synth Biol ; 9(7): 1599-1607, 2020 07 17.
Artigo em Inglês | MEDLINE | ID: mdl-32551507

RESUMO

Protein engineering is an attractive approach for the self-assembly of nanometer-scale architectures for a range of potential nanotechnologies. Using the versatile chemistry provided by protein folding and assembly, coupled with amino acid side-chain functionality, allows for the construction of precise molecular "protein origami" hierarchical patterned structures for a range of nanoapplications such as stand-alone enzymatic pathways and molecular machines. The Staphyloccocus aureus surface protein SasG is a rigid, rod-like structure shown to have high mechanical strength due to "clamp-like" intradomain features and a stabilizing interface between the G5 and E domains, making it an excellent building block for molecular self-assembly. Here we characterize a new two subunit system composed of the SasG rod protein genetically conjugated with de novo designed coiled-coils, resulting in the self-assembly of fibrils. Circular dichroism (CD) and quartz-crystal microbalance with dissipation (QCM-D) are used to show the specific, alternating binding between the two subunits. Furthermore, we use atomic force microscopy (AFM) to study the extent of subunit polymerization in a liquid environment, demonstrating self-assembly culminating in the formation of linear macromolecular fibrils.


Assuntos
Proteínas de Bactérias/metabolismo , Proteínas de Membrana/metabolismo , Engenharia de Proteínas , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Dicroísmo Circular , Proteínas de Membrana/química , Proteínas de Membrana/genética , Microscopia de Força Atômica , Domínios Proteicos , Dobramento de Proteína , Subunidades Proteicas/química , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo , Técnicas de Microbalança de Cristal de Quartzo , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Staphylococcus aureus/metabolismo
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