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1.
Nat Commun ; 15(1): 4611, 2024 May 30.
Artigo em Inglês | MEDLINE | ID: mdl-38816420

RESUMO

G protein-coupled receptors (GPCRs) are pivotal therapeutic targets, but their complex structure poses challenges for effective drug design. Nanobodies, or single-domain antibodies, have emerged as a promising therapeutic strategy to target GPCRs, offering advantages over traditional small molecules and antibodies. However, an incomplete understanding of the structural features enabling GPCR-nanobody interactions has limited their development. In this study, we investigate VUN701, a nanobody antagonist targeting the atypical chemokine receptor 3 (ACKR3). We determine that an extended CDR3 loop is required for ACKR3 binding. Uncommon in most nanobodies, an extended CDR3 is prevalent in GPCR-targeting nanobodies. Combining experimental and computational approaches, we map an inhibitory ACKR3-VUN701 interface and define a distinct conformational mechanism for GPCR inactivation. Our results provide insights into class A GPCR-nanobody selectivity and suggest a strategy for the development of these new therapeutic tools.


Assuntos
Receptores CXCR , Anticorpos de Domínio Único , Anticorpos de Domínio Único/química , Anticorpos de Domínio Único/metabolismo , Humanos , Receptores CXCR/metabolismo , Receptores CXCR/genética , Receptores CXCR/antagonistas & inibidores , Receptores CXCR/química , Células HEK293 , Ligação Proteica , Receptores Acoplados a Proteínas G/metabolismo , Receptores Acoplados a Proteínas G/química , Receptores Acoplados a Proteínas G/antagonistas & inibidores , Animais
2.
ACS Appl Bio Mater ; 7(4): 2325-2337, 2024 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-38483087

RESUMO

This article addresses the entire life cycle of the all-green fibrous materials based on poly(3-hydroxybutyrate) (PHB) containing a natural biocompatible additive Hemin (Hmi): from preparation, service life, and the end of life upon in-soil biodegradation. Fibrous PHB/Hmi materials with a highly developed surface and interconnected porosity were prepared by electrospinning (ES) from Hmi-containing feed solutions. Structural organization of the PHB/Hmi materials (porosity, uniform structure, diameter of fibers, surface area, distribution of Hmi within the PHB matrix, phase composition, etc.) is shown to be governed by the ES conditions: the presence of even minor amounts of Hmi in the PHB/Hmi (below 5 wt %) serves as a powerful tool for the control over their structure, performance, and biodegradation. Service characteristics of the PHB/Hmi materials (wettability, prolonged release of Hmi, antibacterial activity, breathability, and mechanical properties) were studied by different physicochemical methods (scanning electron microscopy, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, differential scanning calorimetry, contact angle measurements, antibacterial tests, etc.). The effect of the structural organization of the PHB/Hmi materials on their in-soil biodegradation at the end of life was analyzed, and key factors providing efficient biodegradation of the PHB/Hmi materials at all stages (from adaptation to mineralization) are highlighted (high surface area and porosity, thin fibers, release of Hmi, etc.). The proposed approach allows for target-oriented preparation and structural design of the functional PHB/Hmi nonwovens when their structural supramolecular organization with a highly developed surface area controls both their service properties as efficient antibacterial materials and in-soil biodegradation upon the end of life.


Assuntos
Materiais Biocompatíveis , Hemina , Animais , Materiais Biocompatíveis/química , Poli-Hidroxibutiratos , Hidroxibutiratos/química , Antibacterianos/química , Estágios do Ciclo de Vida , Morte , Solo
3.
EMBO Mol Med ; 16(3): 445-474, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38355749

RESUMO

TP53-mutant acute myeloid leukemia (AML) and myelodysplastic neoplasms (MDS) are characterized by chemotherapy resistance and represent an unmet clinical need. Chimeric antigen receptor (CAR) T-cells might be a promising therapeutic option for TP53-mutant AML/MDS. However, the impact of TP53 deficiency in AML cells on the efficacy of CAR T-cells is unknown. We here show that CAR T-cells engaging TP53-deficient leukemia cells exhibit a prolonged interaction time, upregulate exhaustion markers, and are inefficient to control AML cell outgrowth in vitro and in vivo compared to TP53 wild-type cells. Transcriptional profiling revealed that the mevalonate pathway is upregulated in TP53-deficient AML cells under CAR T-cell attack, while CAR T-cells engaging TP53-deficient AML cells downregulate the Wnt pathway. In vitro rational targeting of either of these pathways rescues AML cell sensitivity to CAR T-cell-mediated killing. We thus demonstrate that TP53 deficiency confers resistance to CAR T-cell therapy and identify the mevalonate pathway as a therapeutic vulnerability of TP53-deficient AML cells engaged by CAR T-cells, and the Wnt pathway as a promising CAR T-cell therapy-enhancing approach for TP53-deficient AML/MDS.


Assuntos
Leucemia Mieloide Aguda , Ácido Mevalônico , Humanos , Ácido Mevalônico/metabolismo , Via de Sinalização Wnt , Leucemia Mieloide Aguda/genética , Leucemia Mieloide Aguda/terapia , Imunoterapia Adotiva , Linfócitos T , Proteína Supressora de Tumor p53/genética
4.
Biodivers Data J ; 12: e114682, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38222480

RESUMO

Background: Enchytraeids, or potworms, are tiny oligochaetes that are distributed worldwide in many terrestrial, freshwater and marine ecosystems. Despite their key role in the functioning of ecosystems, the diversity and abundance of Enchytraeidae are rarely studied due to the laborious process of species identification. The present study addresses this gap and sheds some light on the distribution and abundance of enchytraeids in the lands of the Northern Palearctic. The provided dataset constitutes the latest and comprehensive field sampling of enchytraeid assemblages across the Asiatic part of the Northern Palearctic, encompassing an original set of soil samples systematically collected throughout the region from 2019 to 2022. New information: The dataset includes occurrences from 131 georeferenced sites, encompassing 39 species and 7,074 records. This represents the first dataset providing species-specific information about the distribution and abundance of terrestrial enchytraeids across an extensive geographic area covering the Asian sector of the Northern Palaearctic. The compiled dataset is the key for exploring and understanding local and regional enchytraeid diversity. It may also serve as a valuable resource for monitoring and conserving the entire soil biodiversity.

5.
Br J Haematol ; 204(5): 1994-1998, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38168722

RESUMO

Pregnancy is a potential trigger of acute thrombotic thrombocytopenic purpura (TTP). The management of pregnancy-associated immune-mediated TTP (iTTP) can be challenging, especially when it is refractory to standard treatment. Caplacizumab, a nanobody to von Willebrand factor (VWF) blocking its A1 domain, is a valuable new therapeutic option. Its use is, however, not approved during pregnancy and breastfeeding. We describe the successful off-label administration of caplacizumab during pregnancy and delivery in a patient with refractory iTTP. The favourable outcome without significant thrombotic or haemorrhagic complications indicates that caplacizumab may be an effective and safe treatment option in refractory iTTP during pregnancy.


Assuntos
Complicações Hematológicas na Gravidez , Púrpura Trombocitopênica Trombótica , Anticorpos de Domínio Único , Humanos , Gravidez , Feminino , Púrpura Trombocitopênica Trombótica/tratamento farmacológico , Púrpura Trombocitopênica Trombótica/imunologia , Anticorpos de Domínio Único/uso terapêutico , Adulto , Complicações Hematológicas na Gravidez/tratamento farmacológico , Fator de von Willebrand/antagonistas & inibidores
6.
Genome Res ; 2023 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-38129077

RESUMO

Paternal genomes are compacted during spermiogenesis and decompacted following fertilization. These processes are fundamental for inheritance but incompletely understood. We analyzed these processes in the frog Xenopus laevis, whose sperm can be assembled into functional pronuclei in egg extracts in vitro. In such extracts, cohesin extrudes DNA into loops, but in vivo cohesin only assembles topologically associating domains (TADs) at the mid-blastula transition (MBT). Why cohesin assembles TADs only at this stage is unknown. We first analyzed genome architecture in frog sperm and compared it to human and mouse. Our results indicate that sperm genome organization is conserved between frogs and humans and occurs without formation of TADs. TADs can be detected in mouse sperm samples, as reported, but these structures might originate from somatic chromatin contaminations. We therefore discuss the possibility that the absence of TADs might be a general feature of vertebrate sperm. To analyze sperm genome remodeling upon fertilization, we reconstituted male pronuclei in Xenopus egg extracts. In pronuclei, chromatin compartmentalization increases, but cohesin does not accumulate at CTCF sites and assemble TADs. However, if pronuclei are formed in the presence of exogenous CTCF, CTCF binds to its consensus sites, and cohesin accumulates at these and forms short-range chromatin loops, which are preferentially anchored at CTCF's N terminus. These results indicate that TADs are only assembled at MBT because before this stage CTCF sites are not occupied and cohesin only forms short-range chromatin loops.

7.
Nanomaterials (Basel) ; 13(22)2023 Nov 10.
Artigo em Inglês | MEDLINE | ID: mdl-37999279

RESUMO

The effect of the aluminum layer on the kinetics and mechanism of aluminum-induced crystallization (AIC) of amorphous silicon (a-Si) in (Al/a-Si)n multilayered films was studied using a complex of in situ methods (simultaneous thermal analysis, transmission electron microscopy, electron diffraction, and four-point probe resistance measurement) and ex situ methods (X-ray diffraction and optical microscopy). An increase in the thickness of the aluminum layer from 10 to 80 nm was found to result in a decrease in the value of the apparent activation energy Ea of silicon crystallization from 137 to 117 kJ/mol (as estimated by the Kissinger method) as well as an increase in the crystallization heat from 12.3 to 16.0 kJ/(mol Si). The detailed kinetic analysis showed that the change in the thickness of an individual Al layer could lead to a qualitative change in the mechanism of aluminum-induced silicon crystallization: with the thickness of Al ≤ 20 nm. The process followed two parallel routes described by the n-th order reaction equation with autocatalysis (Cn-X) and the Avrami-Erofeev equation (An): with an increase in the thickness of Al ≥ 40 nm, the process occurred in two consecutive steps. The first one can be described by the n-th order reaction equation with autocatalysis (Cn-X), and the second one can be described by the n-th order reaction equation (Fn). The change in the mechanism of amorphous silicon crystallization was assumed to be due to the influence of the degree of Al defects at the initial state on the kinetics of the crystallization process.

8.
Front Med (Lausanne) ; 10: 1089087, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37859860

RESUMO

Background: The gold standard for gathering data from electronic health records (EHR) has been manual data extraction; however, this requires vast resources and personnel. Automation of this process reduces resource burdens and expands research opportunities. Objective: This study aimed to determine the feasibility and reliability of automated data extraction in a large registry of adult COVID-19 patients. Materials and methods: This observational study included data from sites participating in the SCCM Discovery VIRUS COVID-19 registry. Important demographic, comorbidity, and outcome variables were chosen for manual and automated extraction for the feasibility dataset. We quantified the degree of agreement with Cohen's kappa statistics for categorical variables. The sensitivity and specificity were also assessed. Correlations for continuous variables were assessed with Pearson's correlation coefficient and Bland-Altman plots. The strength of agreement was defined as almost perfect (0.81-1.00), substantial (0.61-0.80), and moderate (0.41-0.60) based on kappa statistics. Pearson correlations were classified as trivial (0.00-0.30), low (0.30-0.50), moderate (0.50-0.70), high (0.70-0.90), and extremely high (0.90-1.00). Measurements and main results: The cohort included 652 patients from 11 sites. The agreement between manual and automated extraction for categorical variables was almost perfect in 13 (72.2%) variables (Race, Ethnicity, Sex, Coronary Artery Disease, Hypertension, Congestive Heart Failure, Asthma, Diabetes Mellitus, ICU admission rate, IMV rate, HFNC rate, ICU and Hospital Discharge Status), and substantial in five (27.8%) (COPD, CKD, Dyslipidemia/Hyperlipidemia, NIMV, and ECMO rate). The correlations were extremely high in three (42.9%) variables (age, weight, and hospital LOS) and high in four (57.1%) of the continuous variables (Height, Days to ICU admission, ICU LOS, and IMV days). The average sensitivity and specificity for the categorical data were 90.7 and 96.9%. Conclusion and relevance: Our study confirms the feasibility and validity of an automated process to gather data from the EHR.

9.
Mol Cell ; 83(17): 3049-3063.e6, 2023 09 07.
Artigo em Inglês | MEDLINE | ID: mdl-37591243

RESUMO

Cohesin connects CTCF-binding sites and other genomic loci in cis to form chromatin loops and replicated DNA molecules in trans to mediate sister chromatid cohesion. Whether cohesin uses distinct or related mechanisms to perform these functions is unknown. Here, we describe a cohesin hinge mutant that can extrude DNA into loops but is unable to mediate cohesion in human cells. Our results suggest that the latter defect arises during cohesion establishment. The observation that cohesin's cohesion and loop extrusion activities can be partially separated indicates that cohesin uses distinct mechanisms to perform these two functions. Unexpectedly, the same hinge mutant can also not be stopped by CTCF boundaries as well as wild-type cohesin. This suggests that cohesion establishment and cohesin's interaction with CTCF boundaries depend on related mechanisms and raises the possibility that both require transient hinge opening to entrap DNA inside the cohesin ring.


Assuntos
Proteínas de Ciclo Celular , Cromátides , Humanos , Cromátides/genética , Sítios de Ligação , Proteínas de Ciclo Celular/genética , Proteínas Cromossômicas não Histona/genética , Coesinas
10.
Genome Biol ; 24(1): 158, 2023 07 05.
Artigo em Inglês | MEDLINE | ID: mdl-37408019

RESUMO

Genome browsers facilitate integrated analysis of multiple genomics datasets yet visualize only a few regions at a time and lack statistical functions for extracting meaningful information. We present HiCognition, a visual exploration and machine-learning tool based on a new genomic region set concept, enabling detection of patterns and associations between 3D chromosome conformation and collections of 1D genomics profiles of any type. By revealing how transcription and cohesion subunit isoforms contribute to chromosome conformation, we showcase how the flexible user interface and machine learning tools of HiCognition help to understand the relationship between the structure and function of the genome.


Assuntos
Genoma Humano , Genômica , Software , Humanos , Genômica/métodos , Cromossomos Humanos , Aprendizado de Máquina
11.
Chem Commun (Camb) ; 59(65): 9856-9859, 2023 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-37490077

RESUMO

Although non-alkaline rechargeable Zn-air batteries (RZABs) are promising for energy storage, their chemistry is still underdeveloped and unclear. It was suggested that using Zn(OAc)2 or Zn(OTf)2 aqueous solutions as electrolytes enables reversible, corrosion-free charge-discharge processes, but the anodic stability of carbon in these cells has remained poorly studied. We report that CO2 evolution is manifested during the oxygen evolution reaction in non-alkaline RZABs, which is associated with the corrosion of carbon scaffolds. This corrosion is observed for different electrolyte compositions, such as Zn(OAc)2, ZnSO4 and Zn(OTf)2 solutions of various concentrations. The corrosion rate decreases when the overpotentials during the oxygen evolution reaction are lower. This study underlines the importance of addressing the anodic instability of carbon in non-alkaline RZABs.

12.
Front Cell Infect Microbiol ; 13: 1220025, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37457955

RESUMO

Ehrlichia chaffeensis is a tick-transmitted monocytic ehrlichiosis agent primarily causing the disease in people and dogs. We recently described the development and characterization of 55 random mutations in E. chaffeensis, which aided in defining the critical nature of many bacterial genes for its growth in a physiologically relevant canine infection model. In the current study, we tested 45 of the mutants for their infectivity ability to the pathogen's tick vector; Amblyomma americanum. Four mutations resulted in the pathogen's replication deficiency in the tick, similar to the vertebrate host. Mutations causing growth defects in both vertebrate and tick hosts included in genes coding for a predicted alpha/beta hydrolase, a putative dicarboxylate amino acid:cation symporter, a T4SS protein, and predicted membrane-bound proteins. Three mutations caused the bacterial defective growth only in the tick vector, which represented putative membrane proteins. Ten mutations causing no growth defect in the canine host similarly grew well in the tick vector. Mutations in 28 genes/genomic locations causing E. chaffeensis growth attenuation in the canine host were recognized as non-essential for its growth in the tick vector. The tick non-essential genes included genes coding for many metabolic pathway- and outer membrane-associated proteins. This study documents novel vector- and host-specific differences in E. chaffeensis for its functional gene requirements.


Assuntos
Ehrlichia chaffeensis , Ehrlichiose , Carrapatos , Animais , Cães , Carrapatos/microbiologia , Amblyomma , Ehrlichia chaffeensis/metabolismo , Infecção Persistente , Vertebrados , Ehrlichiose/veterinária , Ehrlichiose/microbiologia
13.
Biochemistry (Mosc) ; 88(1): 73-85, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-37068876

RESUMO

Melatonin (N-acetyl-5-methoxytryptamine, MEL), secreted by the pineal gland, plays an important role in regulation of various functions in the human body. There is evidence that MEL exhibits antitumor effect in various types of cancer. We studied the combined effect of MEL and drugs from different pharmacological groups, such as cytarabine (CYT) and navitoclax (ABT-737), on the state of the pool of acute myeloid leukemia (AML) tumor cell using the MV4-11 cell line as model. The combined action of MEL with CYT or ABT-737 contributed to the decrease in proliferative activity of leukemic cells, decrease in the membrane potential of mitochondria, and increase in the production of reactive oxygen species (ROS) and cytosolic Ca2+. We have shown that introduction of MEL together with CYT or ABT-737 increases expression of the C/EBP homologous protein (CHOP) and the autophagy marker LC3A/B and decreases expression of the protein disulfide isomerase (PDI) and binding immunoglobulin protein (BIP), and, therefore, could modulate endoplasmic reticulum (ER) stress and initiate autophagy. The findings support an early suggestion that MEL is able to provide benefits for cancer treatment and be considered as an adjunct to the drugs used in cancer therapy.


Assuntos
Leucemia , Melatonina , Humanos , Melatonina/farmacologia , Melatonina/uso terapêutico , Nitrofenóis/farmacologia , Compostos de Bifenilo/farmacologia , Compostos de Bifenilo/uso terapêutico , Estresse do Retículo Endoplasmático , Leucemia/tratamento farmacológico , Apoptose , Linhagem Celular Tumoral
14.
Int J Mol Sci ; 24(8)2023 Apr 19.
Artigo em Inglês | MEDLINE | ID: mdl-37108680

RESUMO

In the past, our research group was able to successfully remove circulating tumor cells with magnetic nanoparticles. While these cancer cells are typically present in low numbers, we hypothesized that magnetic nanoparticles, besides catching single cells, are also capable of eliminating a large number of tumor cells from the blood ex vivo. This approach was tested in a small pilot study in blood samples of patients suffering from chronic lymphocytic leukemia (CLL), a mature B-cell neoplasm. Cluster of differentiation (CD) 52 is a ubiquitously expressed surface antigen on mature lymphocytes. Alemtuzumab (MabCampath®) is a humanized, IgG1κ, monoclonal antibody directed against CD52, which was formerly clinically approved for treating chronic lymphocytic leukemia (CLL) and therefore regarded as an ideal candidate for further tests to develop new treatment options. Alemtuzumab was bound onto carbon-coated cobalt nanoparticles. The particles were added to blood samples of CLL patients and finally removed, ideally with bound B lymphocytes, using a magnetic column. Flow cytometry quantified lymphocyte counts before, after the first, and after the second flow across the column. A mixed effects analysis was performed to evaluate removal efficiency. p < 0.05 was defined as significant. In the first patient cohort (n = 10), using a fixed nanoparticle concentration, CD19-positive B lymphocytes were reduced by 38% and by 53% after the first and the second purification steps (p = 0.002 and p = 0.005), respectively. In a second patient cohort (n = 11), the nanoparticle concentration was increased, and CD19-positive B lymphocytes were reduced by 44% (p < 0.001) with no further removal after the second purification step. In patients with a high lymphocyte count (>20 G/L), an improved efficiency of approximately 20% was observed using higher nanoparticle concentrations. A 40 to 50% reduction of B lymphocyte count using alemtuzumab-coupled carbon-coated cobalt nanoparticles is feasible, also in patients with a high lymphocyte count. A second purification step did not further increase removal. This proof-of-concept study demonstrates that such particles allow for the targeted extraction of larger amounts of cellular blood components and might offer new treatment options in the far future.


Assuntos
Leucemia Linfocítica Crônica de Células B , Nanopartículas de Magnetita , Humanos , Alemtuzumab/uso terapêutico , Projetos Piloto , Antígenos CD , Antígeno CD52 , Anticorpos Monoclonais Humanizados/uso terapêutico , Antígenos de Neoplasias , Glicoproteínas , Linfócitos , Carbono , Anticorpos Antineoplásicos
15.
Int J Mol Sci ; 24(7)2023 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-37047227

RESUMO

The study reveals the polymer-crosslinker interactions and functionality of hydrophilic nanofibers for antibacterial wound coatings. Coaxial electrospinning leverages a drug encapsulation protocol for a core-shell fiber composite with a core derived from polyvinyl alcohol and polyethylene glycol with amorphous silica (PVA-PEG-SiO2), and a shell originating from polyvinyl alcohol and graphene oxide (PVA-GO). Crosslinking with GO and SiO2 initiates the hydrogel transition for the fiber composite upon contact with moisture, which aims to optimize the drug release. The effect of hydrogel-inducing additives on the drug kinetics is evaluated in the case of chlorhexidine digluconate (CHX) encapsulation in the core of core-shell fiber composite PVA-PEG-SiO2-1x-CHX@PVA-GO. The release rate is assessed with the zero, first-order, Higuchi, and Korsmeyer-Peppas kinetic models, where the inclusion of crosslinking silica provides a longer degradation and release rate. CHX medicated core-shell composite provides sustainable antibacterial activity against Staphylococcus aureus.


Assuntos
Grafite , Nanofibras , Grafite/farmacologia , Álcool de Polivinil , Dióxido de Silício , Hidrogéis/farmacologia , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Bandagens , Nanofibras/uso terapêutico
16.
Int Immunopharmacol ; 119: 110167, 2023 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-37086680

RESUMO

Biomodulina T (InmunyVital®) is a thymic factor that modulates immune response and inflammation. Biomodulina T stimulates the differentiation, maturation and proliferation of T cells. Additionally, Biomodulina T improves the ability of T cells to produce cytokines, therefore enhancing T lymphocyte function. Biomodulina T stimulates the thymus gland and, thus, promotes the recovery of normal thymus size in children with thymic hypoplasia and restores the functions of immunosenescent T cells in aging people. In 1984 Rodriguez Martin RR established the laboratory of Biomodulators, where he created and developed an immunomodulatory thymic factor that he named "Biomodulina T." The biological activity of Biomodulina T was demonstrated in several studies. An extensive series of preclinical toxicological studies were conducted and these studies demonstrated that Biomodulina T is an active and safe thymic factor. Clinical trials were conducted with Biomodulina T in patients with immunodeficiency and infections, autoimmune diseases, older adults with recurrent respiratory infections, and cancer. In 1994, we obtained the approval of Biomodulina T as an immunomodulatory drug. This article identifies the milestones involved in the development of Biomodulina T. Since its discovery more than 35 years ago, reports show that Biomodulina T is a modulator of immune response and inflammation that is very useful for restoring the immune system in young and elderly people with immunodeficiencies, autoimmune diseases, and infections. Biomodulina T is also useful as an immunotherapeutic agent for improving immune responses in cancer and vaccines, for reversing immunosenescence and for improving healthspan in aging.


Assuntos
Doenças Autoimunes , Neoplasias , Masculino , Criança , Humanos , Idoso , Timo , Linfócitos T , Envelhecimento , Fatores Imunológicos/farmacologia , Fatores Imunológicos/uso terapêutico , Adjuvantes Imunológicos , Inflamação
17.
Proc Natl Acad Sci U S A ; 120(11): e2210480120, 2023 03 14.
Artigo em Inglês | MEDLINE | ID: mdl-36897969

RESUMO

Cohesin folds mammalian interphase chromosomes by extruding the chromatin fiber into numerous loops. "Loop extrusion" can be impeded by chromatin-bound factors, such as CTCF, which generates characteristic and functional chromatin organization patterns. It has been proposed that transcription relocalizes or interferes with cohesin and that active promoters are cohesin loading sites. However, the effects of transcription on cohesin have not been reconciled with observations of active extrusion by cohesin. To determine how transcription modulates extrusion, we studied mouse cells in which we could alter cohesin abundance, dynamics, and localization by genetic "knockouts" of the cohesin regulators CTCF and Wapl. Through Hi-C experiments, we discovered intricate, cohesin-dependent contact patterns near active genes. Chromatin organization around active genes exhibited hallmarks of interactions between transcribing RNA polymerases (RNAPs) and extruding cohesins. These observations could be reproduced by polymer simulations in which RNAPs were moving barriers to extrusion that obstructed, slowed, and pushed cohesins. The simulations predicted that preferential loading of cohesin at promoters is inconsistent with our experimental data. Additional ChIP-seq experiments showed that the putative cohesin loader Nipbl is not predominantly enriched at promoters. Therefore, we propose that cohesin is not preferentially loaded at promoters and that the barrier function of RNAP accounts for cohesin accumulation at active promoters. Altogether, we find that RNAP is an extrusion barrier that is not stationary, but rather, translocates and relocalizes cohesin. Loop extrusion and transcription might interact to dynamically generate and maintain gene interactions with regulatory elements and shape functional genomic organization.


Assuntos
Proteínas de Ciclo Celular , Cromatina , Animais , Camundongos , Fator de Ligação a CCCTC/genética , Proteínas de Ciclo Celular/metabolismo , Cromossomos de Mamíferos/metabolismo , RNA Polimerases Dirigidas por DNA/genética , Mamíferos/genética
18.
Wiad Lek ; 76(1): 189-197, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36883509

RESUMO

OBJECTIVE: The aim: To find out the sources of origin, the chronology of ossification, the peculiarities of age-related topographical and anatomical changes in the bones of the human orbit. PATIENTS AND METHODS: Materials and methods: The research was carried out on the specimens of 18 human embryos and prefetuses aged from 4th to 12th weeks of intrauterine development and 12 human fetuses aged from 4th to 9th months which were studied by microscopic examination and 3D reconstruction. RESULTS: Results: The first signs of osteogenesis around the main nervous and visceral contents of the orbit rudiment are observed in 6-week-old embryos in the form of seven cartilaginous bone models. The first signs of ossification in the region of the orbit are found in the maxilla. During the 6th month of intrauterine development, intensive processes of ossification of the frontal, sphenoidal, ethmoidal bones and maxilla are noticeable. From the beginning of the fetal pe¬riod of human ontogenesis, the ossification of bone rudiments that form the walls of the orbit continues. The processes of ossification of the structures of the sphenoidal bone continue, which leads to morphological transformations of the orbit in 5-month-old fetuses - it is separated from the sphenopalatine and infratemporal fossae by a bone layer, the optic canal is formed, and in 6-month-old fetuses, processes of ossification of the frontal, sphenoidal and ethmoidal bones and maxilla occur, Müller's muscle changes its structure to a fibrous one. CONCLUSION: Conclusions: Critical periods of the orbit development are the 6th month of prenatal ontogenesis and the 8th month.


Assuntos
Feto , Osteogênese , Feminino , Gravidez , Humanos , Recém-Nascido , Lactente , Morfogênese , Microscopia , Cuidado Pré-Natal
19.
SLAS Discov ; 28(4): 163-169, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-36841432

RESUMO

The mucosal chemokine CCL28 is a promising target for immunotherapy drug development due to its elevated expression level in epithelial cells and critical role in creating and maintaining an immunosuppressive tumor microenvironment. Using sulfotyrosine as a probe, NMR chemical shift mapping identified a potential receptor-binding hotspot on the human CCL28 surface. CCL28 was screened against 2,678 commercially available chemical fragments by 2D NMR, yielding thirteen verified hits. Computational docking predicted that two fragments could occupy adjoining subsites within the sulfotyrosine recognition cleft. Dual NMR titrations confirmed their ability to bind CCL28 simultaneously, thereby validating an initial fragment pair for linking and merging strategies to design high-potency CCL28 inhibitors.


Assuntos
Quimiocinas CC , Quimiocinas , Humanos , Ligantes , Quimiocinas/metabolismo , Quimiocinas CC/metabolismo , Células Epiteliais/metabolismo , Descoberta de Drogas
20.
Polymers (Basel) ; 16(1)2023 Dec 28.
Artigo em Inglês | MEDLINE | ID: mdl-38201766

RESUMO

Electrospinning of biomimetic materials is of particular interest due to the possibility of producing flexible layers with highly developed surfaces from a wide range of polymers. Additionally, electrospinning is characterized by a high simplicity of implementation and the ability to modify the produced fibrous materials, which resemble structures found in living organisms. This study explores new electrospun materials based on polyhydroxyalkanoates, specifically poly-3-hydroxybutyrate, modified with chlorophyll derivatives. The research investigates the impact of chlorophyll derivatives on the morphology, supramolecular structure, and key properties of nonwoven materials. The obtained results are of interest for the development of new flexible materials with low concentrations of chlorophyll derivatives.

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