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1.
Eur J Nucl Med Mol Imaging ; 50(6): 1792-1810, 2023 05.
Artículo en Inglés | MEDLINE | ID: mdl-36757432

RESUMEN

PURPOSE: Knowledge about pancreatic cancer (PC) biology has been growing rapidly in recent decades. Nevertheless, the survival of PC patients has not greatly improved. The development of a novel methodology suitable for deep investigation of the nature of PC tumors is of great importance. Molecular imaging techniques, such as Fourier transform infrared (FTIR) spectroscopy and Raman hyperspectral mapping (RHM) combined with advanced multivariate data analysis, were useful in studying the biochemical composition of PC tissue. METHODS: Here, we evaluated the potential of molecular imaging in differentiating three groups of PC tumors, which originate from different precursor lesions. Specifically, we comprehensively investigated adenocarcinomas (ACs): conventional ductal AC, intraductal papillary mucinous carcinoma, and ampulla of Vater AC. FTIR microspectroscopy and RHM maps of 24 PC tissue slides were obtained, and comprehensive advanced statistical analyses, such as hierarchical clustering and nonnegative matrix factorization, were performed on a total of 211,355 Raman spectra. Additionally, we employed deep learning technology for the same task of PC subtyping to enable automation. The so-called convolutional neural network (CNN) was trained to recognize spectra specific to each PC group and then employed to generate CNN-prediction-based tissue maps. To identify the DNA methylation spectral markers, we used differently methylated, isolated DNA and compared the observed spectral differences with the results obtained from cellular nuclei regions of PC tissues. RESULTS: The results showed significant differences among cancer tissues of the studied PC groups. The main findings are the varying content of ß-sheet-rich proteins within the PC cells and alterations in the relative DNA methylation level. Our CNN model efficiently differentiated PC groups with 94% accuracy. The usage of CNN in the classification task did not require Raman spectral data preprocessing and eliminated the need for extensive knowledge of statistical methodologies. CONCLUSIONS: Molecular spectroscopy combined with CNN technology is a powerful tool for PC detection and subtyping. The molecular fingerprint of DNA methylation and ß-sheet cytoplasmic proteins established by our results is different for the main PC groups and allowed the subtyping of pancreatic tumors, which can improve patient management and increase their survival. Our observations are of key importance in understanding the variability of PC and allow translation of the methodology into clinical practice by utilizing liquid biopsy testing.


Asunto(s)
Metilación de ADN , Neoplasias Pancreáticas , Humanos , Conformación Proteica en Lámina beta , Neoplasias Pancreáticas/diagnóstico por imagen , Neoplasias Pancreáticas/patología , Análisis Espectral , Neoplasias Pancreáticas
2.
Int J Mol Sci ; 23(7)2022 Mar 24.
Artículo en Inglés | MEDLINE | ID: mdl-35408885

RESUMEN

Even several thousands of DNA lesions are induced in one cell within one day. DNA damage may lead to mutations, formation of chromosomal aberrations, or cellular death. A particularly cytotoxic type of DNA damage is single- and double-strand breaks (SSBs and DSBs, respectively). In this work, we followed DNA conformational transitions induced by the disruption of DNA backbone. Conformational changes of chromatin in living cells were induced by a bleomycin (BLM), an anticancer drug, which generates SSBs and DSBs. Raman micro-spectroscopy enabled to observe chemical changes at the level of single cell and to collect hyperspectral images of molecular structure and composition with sub-micrometer resolution. We applied multivariate data analysis methods to extract key information from registered data, particularly to probe DNA conformational changes. Applied methodology enabled to track conformational transition from B-DNA to A-DNA upon cellular response to BLM treatment. Additionally, increased expression of proteins within the cell nucleus resulting from the activation of repair processes was demonstrated. The ongoing DNA repair process under the BLM action was also confirmed with confocal laser scanning fluorescent microscopy.


Asunto(s)
Bleomicina , Daño del ADN , Bleomicina/farmacología , Aberraciones Cromosómicas , ADN , Reparación del ADN , Humanos
3.
Traffic ; 20(12): 932-942, 2019 12.
Artículo en Inglés | MEDLINE | ID: mdl-31569283

RESUMEN

Fenestrae are open transmembrane pores that are a structural hallmark of healthy liver sinusoidal endothelial cells (LSECs). Their key role is the transport of solutes and macromolecular complexes between the sinusoidal lumen and the space of Disse. To date, the biochemical nature of the cytoskeleton elements that surround the fenestrae and sieve plates in LSECs remain largely elusive. Herein, we took advantage of the latest developments in atomic force imaging and super-resolution fluorescence nanoscopy to define the organization of the supramolecular complex(es) that surround the fenestrae. Our data revealed that spectrin, together with actin, lines the inner cell membrane and provided direct structural support to the membrane-bound pores. We conclusively demonstrated that diamide and iodoacetic acid (IAA) affect fenestrae number by destabilizing the LSEC actin-spectrin scaffold. Furthermore, IAA induces rapid and repeatable switching between the open vs closed state of the fenestrae, indicating that the spectrin-actin complex could play an important role in controlling the pore number. Our results suggest that spectrin functions as a key regulator in the structural preservation of the fenestrae, and as such, it might serve as a molecular target for altering transendothelial permeability.


Asunto(s)
Actinas/metabolismo , Membrana Celular/ultraestructura , Células Endoteliales/ultraestructura , Hígado/ultraestructura , Espectrina/metabolismo , Citoesqueleto de Actina/metabolismo , Citoesqueleto de Actina/ultraestructura , Animales , Membrana Celular/metabolismo , Células Cultivadas , Células Endoteliales/metabolismo , Hígado/irrigación sanguínea , Hígado/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Microscopía de Fuerza Atómica , Imagen Individual de Molécula
4.
Molecules ; 26(21)2021 Oct 27.
Artículo en Inglés | MEDLINE | ID: mdl-34770895

RESUMEN

DNA covers the genetic information in all living organisms. Numerous intrinsic and extrinsic factors may influence the local structure of the DNA molecule or compromise its integrity. Detailed understanding of structural modifications of DNA resulting from interactions with other molecules and surrounding environment is of central importance for the future development of medicine and pharmacology. In this paper, we review the recent achievements in research on DNA structure at nanoscale. In particular, we focused on the molecular structure of DNA revealed by high-resolution AFM (Atomic Force Microscopy) imaging at liquid/solid interfaces. Such detailed structural studies were driven by the technical developments made in SPM (Scanning Probe Microscopy) techniques. Therefore, we describe here the working principles of AFM modes allowing high-resolution visualization of DNA structure under native (liquid) environment. While AFM provides well-resolved structure of molecules at nanoscale, it does not reveal the chemical structure and composition of studied samples. The simultaneous information combining the structural and chemical details of studied analyte allows achieve a comprehensive picture of investigated phenomenon. Therefore, we also summarize recent molecular spectroscopy studies, including Tip-Enhanced Raman Spectroscopy (TERS), on the DNA structure and its structural rearrangements.


Asunto(s)
ADN/química , ADN/ultraestructura , Microscopía de Fuerza Atómica , Conformación de Ácido Nucleico , Análisis Espectral , Microscopía de Fuerza Atómica/métodos , Estructura Molecular , Solventes , Análisis Espectral/métodos , Espectrometría Raman/métodos
5.
Angew Chem Int Ed Engl ; 60(9): 4545-4550, 2021 02 23.
Artículo en Inglés | MEDLINE | ID: mdl-32964527

RESUMEN

Abnormal aggregation of amyloid-ß is a very complex and heterogeneous process. Owing to methodological limitations, the aggregation pathway is still not fully understood. Herein a new approach is presented in which the secondary structure of single amyloid-ß aggregates is investigated with tip-enhanced Raman spectroscopy (TERS) in a liquid environment. Clearly resolved TERS signatures of the amide I and amide III bands enabled a detailed analysis of the molecular structure of single aggregates at each phase of the primary aggregation of amyloid-ß and also of small species on the surface of fibrils attributed to secondary nucleation. Notably, a ß-sheet rearrangement from antiparallel in protofibrils to parallel in fibrils is observed. This study allows better understanding of Alzheimer's disease etiology and the methodology can be applied in studies of other neurodegenerative disorders.


Asunto(s)
Amiloide/química , Imágenes Hiperespectrales/métodos , Espectrometría Raman , Enfermedad de Alzheimer/metabolismo , Enfermedad de Alzheimer/patología , Amiloide/metabolismo , Péptidos beta-Amiloides/química , Humanos , Nanotecnología , Conformación Proteica en Lámina beta
6.
Hepatology ; 69(2): 876-888, 2019 02.
Artículo en Inglés | MEDLINE | ID: mdl-30137644

RESUMEN

The fenestrae of liver sinusoidal endothelial cells (LSECs) allow passive transport of solutes, macromolecules, and particulate material between the sinusoidal lumen and the liver parenchymal cells. Until recently, fenestrae and fenestrae-associated structures were mainly investigated using electron microscopy on chemically fixed LSECs. Hence, the knowledge about their dynamic properties has remained to date largely elusive. Recent progress in atomic force microscopy (AFM) has allowed the study of live cells in three dimensions (X, Y, and Z) over a prolonged time (t) and this at unprecedented speeds and resolving power. Hence, we employed the latest advances in AFM imaging on living LSECs. As a result, we were able to monitor the position, size, and number of fenestrae and sieve plates using four-dimensional AFM (X, Y, Z, and t) on intact LSECs in vitro. During these time-lapse experiments, dynamic data were collected on the origin and morphofunctional properties of the filtration apparatus of LSECs. We present structural evidence on single laying and grouped fenestrae, thereby elucidating their dynamic nature from formation to disappearance. We also collected data on the life span of fenestrae. More especially, the formation and closing of entire sieve plates were observed, and how the continuous rearrangement of sieve plates affects the structure of fenestrae within them was recorded. We observed also the dawn and rise of fenestrae-forming centers and defenestration centers in LSECs under different experimental conditions. Conclusion: Utilizing a multimodal biomedical high-resolution imaging technique we collected fine structural information on the life span, formation, and disappearance of LSEC fenestrae; by doing so, we also gathered evidence on three different pathways implemented in the loss of fenestrae that result in defenestrated LSECs.


Asunto(s)
Células Endoteliales/fisiología , Hígado/citología , Animales , Citocalasina B , Depsipéptidos , Ratones , Microscopía de Fuerza Atómica
7.
Molecules ; 25(3)2020 Jan 28.
Artículo en Inglés | MEDLINE | ID: mdl-32012927

RESUMEN

Every cell in a living organism is constantly exposed to physical and chemical factors which damage the molecular structure of proteins, lipids, and nucleic acids. Cellular DNA lesions are the most dangerous because the genetic information, critical for the identity and function of each eukaryotic cell, is stored in the DNA. In this review, we describe spectroscopic markers of DNA damage, which can be detected by infrared, Raman, surface-enhanced Raman, and tip-enhanced Raman spectroscopies, using data acquired from DNA solutions and mammalian cells. Various physical and chemical DNA damaging factors are taken into consideration, including ionizing and non-ionizing radiation, chemicals, and chemotherapeutic compounds. All major spectral markers of DNA damage are presented in several tables, to give the reader a possibility of fast identification of the spectral signature related to a particular type of DNA damage.


Asunto(s)
Daño del ADN , ADN/efectos de los fármacos , ADN/efectos de la radiación , ADN/química , Humanos , Modelos Moleculares , Conformación Molecular , Radiación/clasificación , Espectrometría Raman
8.
Molecules ; 25(11)2020 May 27.
Artículo en Inglés | MEDLINE | ID: mdl-32471300

RESUMEN

Abnormal protein aggregation has been intensively studied for over 40 years and broadly discussed in the literature due to its significant role in neurodegenerative diseases etiology. Structural reorganization and conformational changes of the secondary structure upon the aggregation determine aggregation pathways and cytotoxicity of the aggregates, and therefore, numerous analytical techniques are employed for a deep investigation into the secondary structure of abnormal protein aggregates. Molecular spectroscopies, including Raman and infrared ones, are routinely applied in such studies. Recently, the nanoscale spatial resolution of tip-enhanced Raman and infrared nanospectroscopies, as well as the high sensitivity of the surface-enhanced Raman spectroscopy, have brought new insights into our knowledge of abnormal protein aggregation. In this review, we order and summarize all nano- and micro-spectroscopic marker bands related to abnormal aggregation. Each part presents the physical principles of each particular spectroscopic technique listed above and a concise description of all spectral markers detected with these techniques in the spectra of neurodegenerative proteins and their model systems. Finally, a section concerning the application of multivariate data analysis for extraction of the spectral marker bands is included.


Asunto(s)
Agregado de Proteínas/fisiología , Amiloide/química , Animales , Humanos , Análisis Multivariante , Análisis de Componente Principal , Espectrometría Raman
9.
J Mol Recognit ; 32(3): e2773, 2019 03.
Artículo en Inglés | MEDLINE | ID: mdl-30565321

RESUMEN

AFMBioMed is the founding name under which international conferences and summer schools are organized around the application of atomic force microscopy in life sciences and nanomedicine. From its inception at the Atomic Energy Commission in Marcoule near 2004 to its creation in 2007 and to its 10th anniversary conference in Krakow, a brief narrative history of its birth and rise will demonstrate how and what such an organization brings to laboratories and the AFM community. With the current planning of the next AFMBioMed conference in Münster in 2019, it will be 15 years of commitment to these events.


Asunto(s)
Microscopía de Fuerza Atómica , Publicaciones Periódicas como Asunto/historia , Congresos como Asunto , Historia del Siglo XX
10.
Phys Chem Chem Phys ; 20(16): 11037-11046, 2018 Apr 25.
Artículo en Inglés | MEDLINE | ID: mdl-29648564

RESUMEN

Understanding the mechanisms involved in the covalent attachment of organic molecules to surfaces is a major challenge for nanotechnology and surface science. On the basis of classical organic chemistry mechanistic considerations, key issues such as selectivity and reactivity of the organic adsorbates could be rationalized and exploited for the design of molecular-scale circuits and devices. Here we use tris(benzocyclobutadieno)triphenylene, a singular Y-shaped hydrocarbon containing antiaromatic cyclobutadienoid rings, as a molecular probe to study the reaction of polycyclic conjugated molecules with atomic scale moieties, dangling-bond (DB) dimers on a hydrogen-passivated Ge(001):H surface. By combining molecular design, synthesis, scanning tunneling microscopy and spectroscopy (STM/STS) and computational modeling, we show that the attachment involves a concerted [4+2] cycloaddition reaction that is completely site-selective and fully reversible. This selectivity, governed by the bond alternation induced by the presence of the cyclobutadienoid rings, allows for the control of the orientation of the molecules with respect to the surface DB-patterning. We also demonstrate that by judicious modification of the electronic levels of the polycyclic benzenoid through substituents, the reaction barrier height can be modified. Finally, we show that after deliberate tip-induced covalent bond cleavage, adsorbed molecules can be used to fine tune the electronic states of the DB dimer. This power to engineer deliberately the bonding configuration and electronic properties opens new perspectives for creating prototypical nanoscale circuitry.

11.
Angew Chem Int Ed Engl ; 57(33): 10500-10505, 2018 Aug 13.
Artículo en Inglés | MEDLINE | ID: mdl-29791082

RESUMEN

A unified approach to the synthesis of the series of higher acenes up to previously unreported undecacene has been developed through the on-surface dehydrogenation of partially saturated precursors. These molecules could be converted into the parent acenes by both atomic manipulation with the tip of a scanning tunneling and atomic force microscope (STM/AFM) as well as by on-surface annealing. The structure of the generated acenes has been visualized by high-resolution non-contact AFM imaging and the evolution of the transport gap with the increase of the number of fused benzene rings has been determined on the basis of scanning tunneling spectroscopy (STS) measurements.

12.
J Mol Recognit ; 30(9)2017 09.
Artículo en Inglés | MEDLINE | ID: mdl-28374551

RESUMEN

The impact of hyperglycemia on adhesion between lung carcinoma cells (A549) and pulmonary human aorta endothelial cells (PHAEC) was studied using the single-cell force spectroscopy. Cancer cells were immobilized on a tipless Atomic Force Microscopy (AFM) cantilever and a single layer of endothelial cells was prepared on a glass slide. The measured force-distance curves provided information about the detachment force and about the frequency of specific ligand-receptor rupture events. Measurements were performed for different times of short term (up to 2 h) and prolonged hyperglycemia (3 h - 24 h). Single-cell force results were correlated with the expression of cell adhesion molecules (intercellular adhesion molecule, P-selectin) and with the length and density of the PHAECs glycocalyx layer, which were measured by AFM nanoindentation. For short-term hyperglycemia, we observed a statistically significant increase of the adhesion parameters that was accompanied by an increase of the glycocalyx length and expression of P-selectin. Removal of hyaluronic acid from PHAECs glycocalyx significantly decreased the adhesion parameters, which indicates that hyaluronic acid has a strong impact on adhesion in A549/PHAEC system in short term of hyperglycemia. For prolonged hyperglycemia, the most significant increase of adhesion parameters was observed for 24 hours and this phenomenon correlated with the expression of adhesion molecules and a decrease of the glycocalyx length. Taking together, presented data indicate that both mechanical and structural properties of the endothelial glycocalyx strongly modulate the adhesion in the A549/PHAEC system.


Asunto(s)
Aorta/citología , Hiperglucemia/metabolismo , Microscopía de Fuerza Atómica/métodos , Adhesión Celular/fisiología , Línea Celular , Glicocálix/metabolismo , Humanos , Selectina-P
13.
Phys Chem Chem Phys ; 18(28): 19309-17, 2016 Jul 28.
Artículo en Inglés | MEDLINE | ID: mdl-27375264

RESUMEN

Dangling bond (DB) arrays on Si(001):H and Ge(001):H surfaces can be patterned with atomic precision and they exhibit complex and rich physics making them interesting from both technological and fundamental perspectives. But their complex behavior often makes scanning tunneling microscopy (STM) images difficult to interpret and simulate. Recently it was shown that low-temperature imaging of unoccupied states of an unpassivated dimer on Ge(001):H results in a symmetric butterfly-like STM pattern, despite the fact that the equilibrium dimer configuration is expected to be a bistable, buckled geometry. Here, based on a thorough characterization of the low-bias switching events on Ge(001):H, we propose a new imaging model featuring a dynamical two-state rate equation. On both Si(001):H and Ge(001):H, this model allows us to reproduce the features of the observed symmetric empty-state images which strongly corroborates the idea that the patterns arise due to fast switching events and provides an insight into the relationship between the tunneling current and switching rates. We envision that our new imaging model can be applied to simulate other bistable systems where fluctuations arise from transiently charged electronic states.

14.
Phys Chem Chem Phys ; 18(5): 3854-61, 2016 Feb 07.
Artículo en Inglés | MEDLINE | ID: mdl-26766161

RESUMEN

Controlling the strength of the coupling between organic molecules and single atoms provides a powerful tool for tuning electronic properties of single-molecule devices. Here, using scanning tunneling microscopy and spectroscopy (STM/STS) supported by theoretical modeling, we study the interaction of a planar organic molecule (trinaphthylene) with a hydrogen-passivated Ge(001):H substrate and a single dangling bond quantum dot on that surface. The electronic structure of the molecule adsorbed on the hydrogen-passivated surface is similar to the gas phase structure and the measurements show that HOMO and LUMO states contribute to the STM filled and empty state images, respectively. Furthermore, we show that the electronic properties are not significantly affected when the molecule is attached to the single dangling bond, which is in contrast with the strong interaction of the molecule with a dangling bond dimer. Our results show that the dangling bond quantum dots could stabilize organic molecules on a hydrogenated semiconductor without affecting their originally designed gas phase electronic properties. Together with the ability to laterally manipulate the molecules on the surface, this will be advantageous in the construction of single-molecule devices, where the coupling and positioning of the molecules on the substrate could be tuned by a proper design of the surface quantum dot arrays, comprising both single and dimerized dangling bonds.

15.
J Chem Phys ; 143(22): 224702, 2015 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-26671391

RESUMEN

Molecular heterostructures are formed from meso-tetraphenyl porphyrins-Zn(II) (ZnTPP) and Cu(II)-phthalocyanines (CuPc) on the rutile TiO2(011) surface. We demonstrate that ZnTPP molecules form a quasi-ordered wetting layer with flat-lying molecules, which provides the support for growth of islands comprised of upright CuPc molecules. The incorporation of the ZnTPP layer and the growth of heterostructures increase the stability of the system and allow for room temperature scanning tunneling microscopy (STM) measurements, which is contrasted with unstable STM probing of only CuPc species on TiO2. We demonstrate that within the CuPc layer the molecules arrange in two phases and we identify molecular dimers as basic building blocks of the dominant structural phase.

16.
J Chem Phys ; 143(9): 094202, 2015 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-26342363

RESUMEN

Functionalized materials consisting of inorganic substrates with organic adsorbates play an increasing role in emerging technologies like molecular electronics or hybrid photovoltaics. For such applications, the adsorption geometry of the molecules under operating conditions, e.g., ambient temperature, is crucial because it influences the electronic properties of the interface, which in turn determine the device performance. So far detailed experimental characterization of adsorbates at room temperature has mainly been done using a combination of complementary methods like photoelectron spectroscopy together with scanning tunneling microscopy. However, this approach is limited to ensembles of adsorbates. In this paper, we show that the characterization of individual molecules at room temperature, comprising the determination of the adsorption configuration and the electrostatic interaction with the surface, can be achieved experimentally by atomic force microscopy (AFM) and Kelvin probe force microscopy (KPFM). We demonstrate this by identifying two different adsorption configurations of isolated copper(ii) meso-tetra (4-carboxyphenyl) porphyrin (Cu-TCPP) on rutile TiO2 (110) in ultra-high vacuum. The local contact potential difference measured by KPFM indicates an interfacial dipole due to electron transfer from the Cu-TCPP to the TiO2. The experimental results are verified by state-of-the-art first principles calculations. We note that the improvement of the AFM resolution, achieved in this work, is crucial for such accurate calculations. Therefore, high resolution AFM at room temperature is promising for significantly promoting the understanding of molecular adsorption.

17.
Redox Biol ; 72: 103162, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38669864

RESUMEN

Protein disulfide isomerases (PDIs) are involved in many intracellular and extracellular processes, including cell adhesion and cytoskeletal reorganisation, but their contribution to the regulation of fenestrations in liver sinusoidal endothelial cells (LSECs) remains unknown. Given that fenestrations are supported on a cytoskeleton scaffold, this study aimed to investigate whether endothelial PDIs regulate fenestration dynamics in primary mouse LSECs. PDIA3 and PDIA1 were found to be the most abundant among PDI isoforms in LSECs. Taking advantage of atomic force microscopy, the effects of PDIA1 or PDIA3 inhibition on the fenestrations in LSECs were investigated using a classic PDIA1 inhibitor (bepristat) and novel aromatic N-sulfonamides of aziridine-2-carboxylic acid derivatives as PDIA1 (C-3389) or PDIA3 (C-3399) inhibitors. The effect of PDIA1 inhibition on liver perfusion was studied in vivo using dynamic contrast-enhanced magnetic resonance imaging. Additionally, PDIA1 inhibitors were examined in vitro in LSECs for effects on adhesion, cytoskeleton organisation, bioenergetics, and viability. Inhibition of PDIA1 with bepristat or C-3389 significantly reduced the number of fenestrations in LSECs, while inhibition of PDIA3 with C-3399 had no effect. Moreover, the blocking of free thiols by the cell-penetrating N-ethylmaleimide, but not by the non-cell-penetrating 4-chloromercuribenzenesulfonate, resulted in LSEC defenestration. Inhibition of PDIA1 did not affect LSEC adhesion, viability, and bioenergetics, nor did it induce a clear-cut rearrangement of the cytoskeleton. However, PDIA1-dependent defenestration was reversed by cytochalasin B, a known fenestration stimulator, pointing to the preserved ability of LSECs to form new pores. Importantly, systemic inhibition of PDIA1 in vivo affected intra-parenchymal uptake of contrast agent in mice consistent with LSEC defenestration. These results revealed the role of intracellular PDIA1 in the regulation of fenestration dynamics in LSECs, and in maintaining hepatic sinusoid homeostasis.


Asunto(s)
Células Endoteliales , Hígado , Proteína Disulfuro Isomerasas , Animales , Masculino , Ratones , Adhesión Celular , Células Cultivadas , Citoesqueleto/metabolismo , Células Endoteliales/metabolismo , Células Endoteliales/citología , Inhibidores Enzimáticos/farmacología , Hígado/metabolismo , Hígado/citología , Proteína Disulfuro Isomerasas/metabolismo , Proteína Disulfuro Isomerasas/antagonistas & inhibidores
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 312: 124026, 2024 May 05.
Artículo en Inglés | MEDLINE | ID: mdl-38368817

RESUMEN

Chromosomes are intranuclear structures, their main function is to store and transmit genetic information during cell division. They are composed of tightly packed DNA in the form of chromatin, which is constantly exposed to various damaging factors. The resulting changes in DNA can have serious consequences (e.g. mutations) if they are not repaired or repaired incorrectly. In this article, we studied chromosomes isolated from human cervical cancer cells (HeLa) exposed to a genotoxic drug causing both single- and double-strand breaks. Specifically, we used bleomycin to induce DNA damage. We followed morphological and chemical changes in chromosomes upon damage induction. Atomic force microscopy was used to visualize the morphology of chromosomes, while Raman microspectroscopy enabled the detection of changes in the chemical structure of chromatin with the resolution close to the diffraction limit. Additionally, we extracted spectra corresponding to chromosome I or chromatin from hyperspectral Raman maps with convolutional neural networks (CNN), which were further analysed with the principal component analysis (PCA) algorithm to reveal molecular markers of DNA damage in chromosomes. The applied multimodal approach revealed simultaneous morphological and molecular changes, including chromosomal aberrations, alterations in DNA conformation, methylation pattern, and increased protein expression upon the bleomycin treatment at the level of the single chromosome.


Asunto(s)
Bleomicina , Cromosomas , Humanos , Bleomicina/farmacología , Metafase , Cromatina , ADN
19.
Spectrochim Acta A Mol Biomol Spectrosc ; 316: 124323, 2024 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-38692104

RESUMEN

Tip-enhanced Raman spectroscopy (TERS) is a label-free analytical technique that characterizes molecular systems, potentially even with a nanometric resolution. In principle, the metallic plasmonic probe is illuminated with a laser beam generating the localized surface plasmons, which induce a strong local electric field enhancement in close proximity to the probe. Such field enhancement improves the Raman scattering cross-section from the sample volume localized near the probe apex. TERS provides a high spatial resolution and a great sensitivity, however, it is rather rarely used due to technical limitations causing unstable enhancement and the relative lack of data reproducibility. Despite many scientific efforts for the fabrication of effective TER probes providing robust TER enhancement still requires further investigations. In this work, we explore new possibilities based on preparation of scanning tunnelling microscopy (STM) plasmonic probes, since by nature of the tunnelling effect, they potentially could offer a very high spatial resolution in STM guided TERS experiments. Here we compare two methods of STM-TERS probe preparation for effective spectra acquisition. Our results strongly indicate that an application of square pulse voltage upon the etching procedure significantly improves the quality of the TER data over those obtained with a constant voltage one. To demonstrate the efficiency of our probes we present the results of hyperspectral TER mapping of the 1,2-dipalmitoyl-sn-glycero-3-phosphoethanolamine (DPPE) monolayer deposited on an ultra-pure and atomically flat gold substrate.

20.
Acta Physiol (Oxf) ; 240(5): e14114, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38391060

RESUMEN

AIM: Chronic heart failure (CHF) is often linked to liver malfunction and systemic endothelial dysfunction. However, whether cardio-hepatic interactions in heart failure involve dysfunction of liver sinusoidal endothelial cells (LSECs) is not known. Here we characterize LSECs phenotype in early and end stages of chronic heart failure in a murine model. METHODS: Right ventricle (RV) function, features of congestive hepatopathy, and the phenotype of primary LSECs were characterized in Tgαq*44 mice, with cardiomyocyte-specific overexpression of the Gαq protein, at the age of 4- and 12-month representative for early and end-stage phases of CHF, respectively. RESULTS: 4- and 12-month-old Tgαq*44 mice displayed progressive impairment of RV function and alterations in hepatic blood flow velocity resulting in hepatic congestion with elevated GGT and bilirubin plasma levels and decreased albumin concentration without gross liver pathology. LSECs isolated from 4- and 12-month-old Tgαq*44 mice displayed significant loss of fenestrae with impaired functional response to cytochalasin B, significant changes in proteome related to cytoskeleton remodeling, and altered vasoprotective function. However, LSECs barrier function and bioenergetics were largely preserved. In 4- and 12-month-old Tgαq*44 mice, LSECs defenestration was associated with prolonged postprandial hypertriglyceridemia and in 12-month-old Tgαq*44 mice with proteomic changes of hepatocytes indicative of altered lipid metabolism. CONCLUSION: Tgαq*44 mice displayed right-sided HF and altered hepatic blood flow leading to LSECs dysfunction involving defenestration, shift in eicosanoid profile, and proteomic changes. LSECs dysfunction appears as an early and persistent event in CHF, preceding congestive hepatopathy and contributing to alterations in lipoprotein transport and CHF pathophysiology.

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