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1.
Interdiscip Sci ; 16(2): 261-288, 2024 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-38955920

RESUMEN

Protein complexes perform diverse biological functions, and obtaining their three-dimensional structure is critical to understanding and grasping their functions. In many cases, it's not just two proteins interacting to form a dimer; instead, multiple proteins interact to form a multimer. Experimentally resolving protein complex structures can be quite challenging. Recently, there have been efforts and methods that build upon prior predictions of dimer structures to attempt to predict multimer structures. However, in comparison to monomeric protein structure prediction, the accuracy of protein complex structure prediction remains relatively low. This paper provides an overview of recent advancements in efficient computational models for predicting protein complex structures. We introduce protein-protein docking methods in detail and summarize their main ideas, applicable modes, and related information. To enhance prediction accuracy, other critical protein-related information is also integrated, such as predicting interchain residue contact, utilizing experimental data like cryo-EM experiments, and considering protein interactions and non-interactions. In addition, we comprehensively review computational approaches for end-to-end prediction of protein complex structures based on artificial intelligence (AI) technology and describe commonly used datasets and representative evaluation metrics in protein complexes. Finally, we analyze the formidable challenges faced in current protein complex structure prediction tasks, including the structure prediction of heteromeric complex, disordered regions in complex, antibody-antigen complex, and RNA-related complex, as well as the evaluation metrics for complex assessment. We hope that this work will provide comprehensive knowledge of complex structure predictions to contribute to future advanced predictions.


Asunto(s)
Proteínas , Proteínas/química , Proteínas/metabolismo , Biología Computacional/métodos , Conformación Proteica , Simulación del Acoplamiento Molecular , Inteligencia Artificial , Bases de Datos de Proteínas
2.
ACS Nano ; 2024 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-39038109

RESUMEN

Cancer immunotherapy has emerged as a promising approach for the treatment of various cancers. However, the immunosuppressive tumor microenvironment (TME) limits the efficacy of current immunotherapies. In this study, we designed a dual-responsive DNA methyltransferase inhibitor nanoprodrug ACNPs for combination therapy with oncolytic herpes simplex virus (oHSV). We found that the epigenetic inhibitor 5-Azacytidine (5-Aza) upregulated gasdermin E (GSDME) expression at the gene level, whereas the oHSV decreased the ubiquitination and degradation of GSDME to elevate its levels. Based on these observations, we further discovered that ACNPs and oHSV synergistically enhanced GSDME-mediated pyroptosis. Additionally, the combination therapy of ACNPs and oHSV effectively inhibited tumor growth, remodeled the immunosuppressive TME, and improved the efficacy of immune checkpoint blockade (ICB) therapy. These results demonstrate the potential to overcome immunosuppression through synergistic combinations, offering a promising approach for cancer immunotherapy.

3.
Plant Commun ; : 101041, 2024 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-39030906

RESUMEN

Diatoms, a group of prevalent marine algae, significantly contribute to global primary productivity. Their substantial biomass is linked to enhanced absorption of blue-green light underwater, facilitated by fucoxanthin chlorophyll a/c-binding proteins (FCPs), exhibiting oligomeric diversity across diatom species. Utilizing mild CN-PAGE analysis on solubilized thylakoid membranes, we displayed monomeric, dimeric, trimeric, tetrameric and pentameric FCPs in diatoms. Mass spectrometry analysis revealed each oligomeric FCP has specific protein compositions, constituting a large Lhcf family of FCP antennas. In addition, we resolved the structures of Thalassiosira pseudonana FCP (Tp-FCP) homotrimer and Chaetoceros gracilis FCP (Cg-FCP) pentamer by cryo-electron microscopy at 2.73 Å and 2.65 Å resolutions, respectively. The distinct pigment composition and organization in various oligomeric FCPs change their blue-green light-harvesting, excitation energy transfer pathways. In comparison to dimeric and trimeric FCPs, Cg-FCP tetramer and Cg-FCP pentamer exhibit stronger absorption by Chls c, red-shifted and broader Chl a fluorescence emission, as well as more robust circular dichroism signals originating from Chl a-carotenoid dimers. These spectroscopic characteristics indicate that Chl a molecules in Cg-FCP tetramer and Cg-FCP pentamer are more heterogeneous than in both dimers and Tp-FCP trimer. The structural and spectroscopic insights provided by this study contribute to a better understanding of the mechanisms that empower diatoms to adapt to fluctuating light environments.

4.
Acta Biomater ; 183: 30-49, 2024 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-38849022

RESUMEN

Bone, an actively metabolic organ, undergoes constant remodeling throughout life. Disturbances in the bone microenvironment can be responsible for pathologically bone diseases such as periodontitis, osteoarthritis, rheumatoid arthritis and osteoporosis. Conventional bone tissue biomaterials are not adequately adapted to complex bone microenvironment. Therefore, there is an urgent clinical need to find an effective strategy to improve the status quo. In recent years, nanotechnology has caused a revolution in biomedicine. Cerium(III, IV) oxide, as an important member of metal oxide nanomaterials, has dual redox properties through reversible binding with oxygen atoms, which continuously cycle between Ce(III) and Ce(IV). Due to its special physicochemical properties, cerium(III, IV) oxide has received widespread attention as a versatile nanomaterial, especially in bone diseases. This review describes the characteristics of bone microenvironment. The enzyme-like properties and biosafety of cerium(III, IV) oxide are also emphasized. Meanwhile, we summarizes controllable synthesis of cerium(III, IV) oxide with different nanostructural morphologies. Following resolution of synthetic principles of cerium(III, IV) oxide, a variety of tailored cerium-based biomaterials have been widely developed, including bioactive glasses, scaffolds, nanomembranes, coatings, and nanocomposites. Furthermore, we highlight the latest advances in cerium-based biomaterials for inflammatory and metabolic bone diseases and bone-related tumors. Tailored cerium-based biomaterials have already demonstrated their value in disease prevention, diagnosis (imaging and biosensors) and treatment. Therefore, it is important to assist in bone disease management by clarifying tailored properties of cerium(III, IV) oxide in order to promote the use of cerium-based biomaterials in the future clinical setting. STATEMENT OF SIGNIFICANCE: In this review, we focused on the promising of cerium-based biomaterials for bone diseases. We reviewed the key role of bone microenvironment in bone diseases and the main biological activities of cerium(III, IV) oxide. By setting different synthesis conditions, cerium(III, IV) oxide nanostructures with different morphologies can be controlled. Meanwhile, tailored cerium-based biomaterials can serve as a versatile toolbox (e.g., bioactive glasses, scaffolds, nanofibrous membranes, coatings, and nanocomposites). Then, the latest research advances based on cerium-based biomaterials for the treatment of bone diseases were also highlighted. Most importantly, we analyzed the perspectives and challenges of cerium-based biomaterials. In future perspectives, this insight has given rise to a cascade of cerium-based biomaterial strategies, including disease prevention, diagnosis (imaging and biosensors) and treatment.


Asunto(s)
Materiales Biocompatibles , Enfermedades Óseas , Cerio , Cerio/química , Cerio/uso terapéutico , Humanos , Materiales Biocompatibles/química , Materiales Biocompatibles/uso terapéutico , Enfermedades Óseas/tratamiento farmacológico , Animales
5.
Nat Commun ; 15(1): 3669, 2024 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-38693119

RESUMEN

Oncolytic viruses (OVs) show promise as a cancer treatment by selectively replicating in tumor cells and promoting antitumor immunity. However, the current immunogenicity induced by OVs for tumor treatment is relatively weak, necessitating a thorough investigation of the mechanisms underlying its induction of antitumor immunity. Here, we show that HSV-1-based OVs (oHSVs) trigger ZBP1-mediated PANoptosis (a unique innate immune inflammatory cell death modality), resulting in augmented antitumor immune effects. Mechanistically, oHSV enhances the expression of interferon-stimulated genes, leading to the accumulation of endogenous Z-RNA and subsequent activation of ZBP1. To further enhance the antitumor potential of oHSV, we conduct a screening and identify Fusobacterium nucleatum outer membrane vesicle (Fn-OMV) that can increase the expression of PANoptosis execution proteins. The combination of Fn-OMV and oHSV demonstrates potent antitumor immunogenicity. Taken together, our study provides a deeper understanding of oHSV-induced antitumor immunity, and demonstrates a promising strategy that combines oHSV with Fn-OMV.


Asunto(s)
Fusobacterium nucleatum , Herpesvirus Humano 1 , Viroterapia Oncolítica , Virus Oncolíticos , Proteínas de Unión al ARN , Herpesvirus Humano 1/inmunología , Herpesvirus Humano 1/genética , Virus Oncolíticos/genética , Virus Oncolíticos/inmunología , Animales , Humanos , Viroterapia Oncolítica/métodos , Ratones , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo , Proteínas de Unión al ARN/inmunología , Línea Celular Tumoral , Fusobacterium nucleatum/inmunología , Neoplasias/terapia , Neoplasias/inmunología , Femenino , Inmunidad Innata , Ratones Endogámicos BALB C
6.
Heliyon ; 10(10): e31347, 2024 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-38803949

RESUMEN

6-phosphofructo-2-kinase/fructose-2,6-biphosphatase-3 (PFKFB3) influences cancer progression via participating in tumor aerobic glycolysis. In this study, we aimed to evaluate the prognostic significance of PFKFB3 in bladder cancer (BLCA) patients by analyzing a combination of publicly available databases, clinical patient data, and bladder tumor samples from our hospital. Single-cell and bulk RNA-seq data of bladder cancer, obtained from ENA, GEO, and TCGA databases, were utilized for our analysis. The results indicated that PFKFB3 mRNA expression was markedly elevated in bladder cancer compared to paired normal tissue. Furthermore, BLCA patients with high PFKFB3 expression exhibited a significantly worse prognosis (P < 0.05). To validate these findings, clinical data and immunohistochemistry staining were performed on specimens obtained from 89 BLCA patients who underwent radical cystectomy at either Qingdao University Affiliated Hospital or Peking Union Medical College Hospital. The findings from this verification process confirmed that high expression of PFKFB3 serves as a biomarker for predicting worse prognosis in BLCA patients (OR: 2.462, 95 % CI: 1.202-5.042, P = 0.012). To facilitate clinical application, we developed a nomogram based on four variables, including PFKFB3 expression, to predict the survival of BLCA patients. Importantly, this nomogram demonstrated a low mean prediction error of 0.03. Taken together, our findings suggest that PFKFB3 has the potential to serve as both a prognostic biomarker and a therapeutic target for BLCA patients.

7.
Nat Commun ; 15(1): 4535, 2024 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-38806516

RESUMEN

Cryptophyte algae are an evolutionarily distinct and ecologically important group of photosynthetic unicellular eukaryotes. Photosystem II (PSII) of cryptophyte algae associates with alloxanthin chlorophyll a/c-binding proteins (ACPs) to act as the peripheral light-harvesting system, whose supramolecular organization is unknown. Here, we purify the PSII-ACPII supercomplex from a cryptophyte alga Chroomonas placoidea (C. placoidea), and analyze its structure at a resolution of 2.47 Å using cryo-electron microscopy. This structure reveals a dimeric organization of PSII-ACPII containing two PSII core monomers flanked by six symmetrically arranged ACPII subunits. The PSII core is conserved whereas the organization of ACPII subunits exhibits a distinct pattern, different from those observed so far in PSII of other algae and higher plants. Furthermore, we find a Chl a-binding antenna subunit, CCPII-S, which mediates interaction of ACPII with the PSII core. These results provide a structural basis for the assembly of antennas within the supercomplex and possible excitation energy transfer pathways in cryptophyte algal PSII, shedding light on the diversity of supramolecular organization of photosynthetic machinery.


Asunto(s)
Microscopía por Crioelectrón , Criptófitas , Complejo de Proteína del Fotosistema II , Complejo de Proteína del Fotosistema II/metabolismo , Complejo de Proteína del Fotosistema II/química , Criptófitas/metabolismo , Clorofila/metabolismo , Proteínas de Unión a Clorofila/metabolismo , Proteínas de Unión a Clorofila/química , Multimerización de Proteína , Clorofila A/metabolismo , Clorofila A/química , Modelos Moleculares , Complejos de Proteína Captadores de Luz/metabolismo , Complejos de Proteína Captadores de Luz/química
8.
J Phys Chem Lett ; 15(22): 5838-5847, 2024 Jun 06.
Artículo en Inglés | MEDLINE | ID: mdl-38788163

RESUMEN

The light-harvesting complexes (LHCs) of diatoms, specifically fucoxanthin-Chl a/c binding proteins (FCPs), exhibit structural and functional diversity, as highlighted by recent structural studies of photosystem II-FCP (PSII-FCPII) supercomplexes from different diatom species. The excitation dynamics of PSII-FCPII supercomplexes isolated from the diatom Thalassiosira pseudonana was explored using time-resolved fluorescence spectroscopy and two-dimensional electronic spectroscopy at room temperature and 77 K. Energy transfer between FCPII and PSII occurred remarkably fast (<5 ps), emphasizing the efficiency of FCPII as a light-harvesting antenna. The presence of long-wavelength chlorophylls may further help concentrate excitations in the core complex and increase the efficiency of light harvesting. Structure-based calculations reveal remarkably strong excitonic couplings between chlorophylls in the FCP antenna and between FCP and the PSII core antenna that are the basis for the rapid energy transfer.


Asunto(s)
Diatomeas , Transferencia de Energía , Complejos de Proteína Captadores de Luz , Complejo de Proteína del Fotosistema II , Complejo de Proteína del Fotosistema II/química , Complejo de Proteína del Fotosistema II/metabolismo , Diatomeas/química , Diatomeas/metabolismo , Complejos de Proteína Captadores de Luz/química , Complejos de Proteína Captadores de Luz/metabolismo , Espectrometría de Fluorescencia , Clorofila/química
9.
J Am Chem Soc ; 146(15): 10432-10442, 2024 Apr 17.
Artículo en Inglés | MEDLINE | ID: mdl-38498436

RESUMEN

As an efficient and clean energy carrier, hydrogen is expected to play a key role in future energy systems. However, hydrogen-storage technology must be safe with a high hydrogen-storage density, which is difficult to achieve. MgH2 is a promising solid-state hydrogen-storage material owing to its large hydrogen-storage capacity (7.6 wt %) and excellent reversibility, but its large-scale utilization is restricted by slow hydrogen-desorption kinetics. Although catalysts can improve the hydrogen-storage kinetics of MgH2, they reduce the hydrogen-storage capacity. Single-atom catalysts maximize the atom utilization ratio and the number of interfacial sites to boost the catalytic activity, while easy aggregation at high temperatures limits further application. Herein, we designed a single-atom Ni-loaded TiO2 catalyst with superior thermal stability and catalytic activity. The optimized 15wt%-Ni0.034@TiO2 catalyst reduced the onset dehydrogenation temperature of MgH2 to 200 °C. At 300 °C, the H2 released and absorbed 4.6 wt % within 5 min and 6.53 wt % within 10 s, respectively. The apparent activation energies of MgH2 dehydrogenation and hydrogenation were reduced to 64.35 and 35.17 kJ/mol of H2, respectively. Even after 100 cycles of hydrogenation and dehydrogenation, there was still a capacity retention rate of 97.26%. The superior catalytic effect is attributed to the highly synergistic catalytic activity of single-atom Ni, numerous oxygen vacancies, and multivalent Tix+ in the TiO2 support, in which the single-atom Ni plays the dominant role, accelerating electron transfer between Mg2+ and H- and weakening the Mg-H bonds. This work paves the way for superior hydrogen-storage materials for practical unitization and also extends the application of single-atom catalysis in high-temperature solid-state reactions.

10.
Interdiscip Sci ; 2024 Mar 27.
Artículo en Inglés | MEDLINE | ID: mdl-38536590

RESUMEN

Protein complex structure prediction is an important problem in computational biology. While significant progress has been made for protein monomers, accurate evaluation of protein complexes remains challenging. Existing assessment methods in CASP, lack dedicated metrics for evaluating complexes. DockQ, a widely used metric, has some limitations. In this study, we propose a novel metric called BDM (Based on Distance difference Matrix) for assessing protein complex prediction structures. Our approach utilizes a distance difference matrix derived from comparing real and predicted protein structures, establishing a linear correlation with Root Mean Square Deviation (RMSD). BDM overcomes limitations associated with receptor-ligand differentiation and eliminates the requirement for structure alignment, making it a more effective and efficient metric. Evaluation of BDM using CASP14 and CASP15 test sets demonstrates superior performance compared to the official CASP scoring. BDM provides accurate and reasonable assessments of predicted protein complexes, wide adoption of BDM has the potential to advance protein complex structure prediction and facilitate related researches across scientific domains. Code is available at http://mialab.ruc.edu.cn/BDMServer/ .

11.
Proc Natl Acad Sci U S A ; 121(7): e2315476121, 2024 Feb 13.
Artículo en Inglés | MEDLINE | ID: mdl-38319970

RESUMEN

Marine photosynthetic dinoflagellates are a group of successful phytoplankton that can form red tides in the ocean and also symbiosis with corals. These features are closely related to the photosynthetic properties of dinoflagellates. We report here three structures of photosystem I (PSI)-chlorophylls (Chls) a/c-peridinin protein complex (PSI-AcpPCI) from two species of dinoflagellates by single-particle cryoelectron microscopy. The crucial PsaA/B subunits of a red tidal dinoflagellate Amphidinium carterae are remarkably smaller and hence losing over 20 pigment-binding sites, whereas its PsaD/F/I/J/L/M/R subunits are larger and coordinate some additional pigment sites compared to other eukaryotic photosynthetic organisms, which may compensate for the smaller PsaA/B subunits. Similar modifications are observed in a coral symbiotic dinoflagellate Symbiodinium species, where two additional core proteins and fewer AcpPCIs are identified in the PSI-AcpPCI supercomplex. The antenna proteins AcpPCIs in dinoflagellates developed some loops and pigment sites as a result to accommodate the changed PSI core, therefore the structures of PSI-AcpPCI supercomplex of dinoflagellates reveal an unusual protein assembly pattern. A huge pigment network comprising Chls a and c and various carotenoids is revealed from the structural analysis, which provides the basis for our deeper understanding of the energy transfer and dissipation within the PSI-AcpPCI supercomplex, as well as the evolution of photosynthetic organisms.


Asunto(s)
Antozoos , Dinoflagelados , Animales , Antozoos/metabolismo , Complejos de Proteína Captadores de Luz/metabolismo , Dinoflagelados/metabolismo , Floraciones de Algas Nocivas , Simbiosis , Microscopía por Crioelectrón , Complejo de Proteína del Fotosistema I/metabolismo , Clorofila/metabolismo
12.
Sci Adv ; 10(8): eadk7140, 2024 Feb 23.
Artículo en Inglés | MEDLINE | ID: mdl-38394197

RESUMEN

Acaryochloris marina is a unique cyanobacterium using chlorophyll d (Chl d) as its major pigment and thus can use far-red light for photosynthesis. Photosystem II (PSII) of A. marina associates with a number of prochlorophyte Chl-binding (Pcb) proteins to act as the light-harvesting system. We report here the cryo-electron microscopic structure of a PSII-Pcb megacomplex from A. marina at a 3.6-angstrom overall resolution and a 3.3-angstrom local resolution. The megacomplex is organized as a tetramer consisting of two PSII core dimers flanked by sixteen symmetrically related Pcb proteins, with a total molecular weight of 1.9 megadaltons. The structure reveals the detailed organization of PSII core consisting of 15 known protein subunits and an unknown subunit, the assembly of 4 Pcb antennas within each PSII monomer, and possible pathways of energy transfer within the megacomplex, providing deep insights into energy transfer and dissipation mechanisms within the PSII-Pcb megacomplex involved in far-red light utilization.


Asunto(s)
Complejo de Proteína del Fotosistema II , Proclorofitas , Complejo de Proteína del Fotosistema II/metabolismo , Clorofila/metabolismo , Fotosíntesis
13.
Nat Commun ; 14(1): 8164, 2023 Dec 09.
Artículo en Inglés | MEDLINE | ID: mdl-38071196

RESUMEN

Diatoms are dominant marine algae and contribute around a quarter of global primary productivity, the success of which is largely attributed to their photosynthetic capacity aided by specific fucoxanthin chlorophyll-binding proteins (FCPs) to enhance the blue-green light absorption under water. We purified a photosystem II (PSII)-FCPII supercomplex and a trimeric FCP from Cyclotella meneghiniana (Cm) and solved their structures by cryo-electron microscopy (cryo-EM). The structures reveal detailed organizations of monomeric, dimeric and trimeric FCP antennae, as well as distinct assemblies of Lhcx6_1 and dimeric FCPII-H in PSII core. Each Cm-PSII-FCPII monomer contains an Lhcx6_1, an FCP heterodimer and other three FCP monomers, which form an efficient pigment network for harvesting energy. More diadinoxanthins and diatoxanthins are found in FCPs, which may function to quench excess energy. The trimeric FCP contains more chlorophylls c and fucoxanthins. These diversified FCPs and PSII-FCPII provide a structural basis for efficient light energy harvesting, transfer, and dissipation in C. meneghiniana.


Asunto(s)
Diatomeas , Complejo de Proteína del Fotosistema II , Complejo de Proteína del Fotosistema II/metabolismo , Diatomeas/metabolismo , Microscopía por Crioelectrón , Proteínas de Unión a Clorofila/química , Fotosíntesis , Complejos de Proteína Captadores de Luz/metabolismo
14.
ACS Nano ; 17(23): 23262-23298, 2023 Dec 12.
Artículo en Inglés | MEDLINE | ID: mdl-38010076

RESUMEN

Cancer stem cells (CSCs) drive tumor initiation, progression, and therapeutic resistance due to their self-renewal and differentiation capabilities. Despite encouraging progress in cancer treatment, conventional approaches often fail to eliminate CSCs, necessitating the development of precise targeted strategies. Recent advances in materials science and nanotechnology have enabled promising CSC-targeted approaches, harnessing the power of tailoring nanomaterials in diverse therapeutic applications. This review provides an update on the current landscape of nanobased precision targeting approaches against CSCs. We elucidate the nuanced application of organic, inorganic, and bioinspired nanomaterials across a spectrum of therapeutic paradigms, encompassing targeted therapy, immunotherapy, and multimodal synergistic therapies. By examining the accomplishments and challenges in this potential field, we aim to inform future efforts to advance nanomaterial-based therapies toward more effective "sniping" of CSCs and tumor clearance.


Asunto(s)
Nanoestructuras , Neoplasias , Humanos , Neoplasias/tratamiento farmacológico , Diferenciación Celular , Inmunoterapia , Células Madre Neoplásicas/patología
15.
Sci Adv ; 9(43): eadi8446, 2023 10 27.
Artículo en Inglés | MEDLINE | ID: mdl-37878698

RESUMEN

Diatoms rely on fucoxanthin chlorophyll a/c-binding proteins (FCPs) for their great success in oceans, which have a great diversity in their pigment, protein compositions, and subunit organizations. We report a unique structure of photosystem II (PSII)-FCPII supercomplex from Thalassiosira pseudonana at 2.68-Å resolution by cryo-electron microscopy. FCPIIs within this PSII-FCPII supercomplex exist in dimers and monomers, and a homodimer and a heterodimer were found to bind to a PSII core. The FCPII homodimer is formed by Lhcf7 and associates with PSII through an Lhcx family antenna Lhcx6_1, whereas the heterodimer is formed by Lhcf6 and Lhcf11 and connects to the core together with an Lhcf5 monomer through Lhca2 monomer. An extended pigment network consisting of diatoxanthins, diadinoxanthins, fucoxanthins, and chlorophylls a/c is revealed, which functions in efficient light harvesting, energy transfer, and dissipation. These results provide a structural basis for revealing the energy transfer and dissipation mechanisms and also for the structural diversity of FCP antennas in diatoms.


Asunto(s)
Diatomeas , Complejo de Proteína del Fotosistema II , Complejo de Proteína del Fotosistema II/química , Clorofila A/metabolismo , Diatomeas/química , Microscopía por Crioelectrón , Proteínas de Unión a Clorofila/química , Proteínas de Unión a Clorofila/metabolismo , Polímeros/metabolismo
16.
Gels ; 9(9)2023 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-37754389

RESUMEN

A simple and cost-effective method for the fabrication of a safe, dual-responsive, highly stretchable, self-healing and injectable hydrogel is reported based on a combination of dynamic boronate ester bonds and hydrogen bonding interactions. The mechanical properties of the hydrogel are tunable by adjusting the molar ratios between sugar moieties on the polymer and borax. It was remarkable to note that the 2:1 ratio of sugar and borate ion significantly improves the mechanical strength of the hydrogel. The injectability, self-healing and stretchability properties of the hydrogel were also examined. In addition, the impact of the variation of the pH and the addition of free sugar responsiveness of the hydrogel was studied. High MRC-5 cell viability was noticed by the 3D live/dead assay after 24 h cell culture within the hydrogel scaffold. Hence, the developed hydrogels have desirable features that warrant their applications for drug delivery, scaffolds for cell and tissue engineering.

17.
Structure ; 31(10): 1247-1258.e3, 2023 10 05.
Artículo en Inglés | MEDLINE | ID: mdl-37633266

RESUMEN

Light-harvesting complexes of photosystem II (LHCIIs) in green algae and plants are vital antenna apparatus for light harvesting, energy transfer, and photoprotection. Here we determined the structure of a siphonous-type LHCII trimer from the intertidal green alga Bryopsis corticulans by X-ray crystallography and cryo-electron microscopy (cryo-EM), and analyzed its functional properties by spectral analysis. The Bryopsis LHCII (Bry-LHCII) structures in both homotrimeric and heterotrimeric form show that green light-absorbing siphonaxanthin and siphonein occupied the sites of lutein and violaxanthin in plant LHCII, and two extra chlorophylls (Chls) b replaced Chls a. Binding of these pigments expands the blue-green light absorption of B. corticulans in the tidal zone. We observed differences between the Bry-LHCII homotrimer crystal and cryo-EM structures, and also between Bry-LHCII homotrimer and heterotrimer cryo-EM structures. These conformational changes may reflect the flexibility of Bry-LHCII, which may be required to adapt to light fluctuations from tidal rhythms.


Asunto(s)
Chlorophyta , Complejos de Proteína Captadores de Luz , Microscopía por Crioelectrón , Complejos de Proteína Captadores de Luz/química , Complejos de Proteína Captadores de Luz/metabolismo , Chlorophyta/metabolismo , Tilacoides , Complejo de Proteína del Fotosistema II/química , Complejo de Proteína del Fotosistema II/metabolismo
18.
Front Endocrinol (Lausanne) ; 14: 1171045, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37529597

RESUMEN

Background: Due to the location of paragangliomas (PGLs) behind the retrohepatic segment of inferior vena cava (IVC), it is difficult to expose and resect the tumor. Case presentation: A tumor measuring 50×45×62cm behind the retrohepatic portion of IVC was found in a 51-year-old female with hypertention and diabetes mellitus. Although the test for catecholamines revealed no signs of disease, the enhanced computed tomography (CT) scan, somatostatin receptor imaging and iodine-131-labeled metaiiodo-benzylguanidine (131I-MIBG) imaging revealed that the tumor was PGL. A three-dimensional printing was performed to visualize the tumor. The laparoscpic surgery for the PGL behind the retrohepatic segment of IVC was performed and the tumor was resected completely without causing any tissues injury. The pathologic diagnosis was PGL and the patient was able to recover well. Conclusions: This case demonstrates that laparoscopic surgery may be helpful in tumor accessibility, and could be used in the appropriate cases to remove PGLs that are located behind the retrohepatic segment of the IVC.


Asunto(s)
Laparoscopía , Paraganglioma , Femenino , Humanos , Persona de Mediana Edad , Vena Cava Inferior/diagnóstico por imagen , Vena Cava Inferior/cirugía , Vena Cava Inferior/lesiones , Paraganglioma/diagnóstico por imagen , Paraganglioma/cirugía , Paraganglioma/patología , Laparoscopía/métodos
19.
J Phys Chem Lett ; 14(35): 7967-7974, 2023 Sep 07.
Artículo en Inglés | MEDLINE | ID: mdl-37647015

RESUMEN

Fucoxanthin-chlorophyll proteins (FCPs) are a family of photosynthetic light-harvesting complex (LHC) proteins found in diatoms. They efficiently capture photons and regulate their functions, ensuring diatom survival in highly fluctuating light. FCPs are present in different oligomeric states in vivo, but functional differences among these FCP oligomers are not yet fully understood. Here we characterized two types of antenna complexes (FCP-B/C dimers and FCP-A tetramers) that coexist in the marine centric diatom Chaetoceros gracilis using both time-resolved fluorescence and transient absorption spectroscopy. We found that the FCP-B/C complex did not show fluorescence quenching, whereas FCP-A was severely quenched, via an ultrafast excitation energy transfer (EET) pathway from Chl a Qy to the fucoxanthin S1/ICT state. These results highlight the functional differences between FCP dimers and tetramers and indicate that the EET pathway from Chl a to carotenoids is an energy dissipation mechanism conserved in a variety of photosynthetic organisms.


Asunto(s)
Carotenoides , Diatomeas , Clorofila A , Proteínas de Unión a Clorofila , Citoplasma , Polímeros
20.
Ann Anat ; 250: 152136, 2023 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-37506776

RESUMEN

BACKGROUND: Our previous study has confirmed that constraint-induced movement therapy (CIMT) could promote neural remodeling in hemiplegic cerebral palsy (HCP) mice through Nogo-A/NgR/RhoA/ROCK signaling, however, the upstream mechanism was still unclear. Therefore, the present study aimed to further explore the mechanism of CIMT regulating the expression of Nogo-A in HCP mice. METHOD: HCP mice were well established through ligating the left common carotid artery of 7-day-old pups and being placed in a hypoxic box which was filled with a mixture of 8% oxygen and 92% nitrogen. CIMT intervention was conducted by taping to fix the entire arm of the contralateral side (left) to force the mice to use the affected limb (right). Bioinformatics prediction and luciferase experiment were performed to confirm that miR-182-5p was targeted with Nogo-A. The beam test and grip test were applied to examine the behavioral performance under the intervention of c-Jun and CIMT. Also, immunofluorescence, Golgi staining, and transmission electron microscopy were conducted to show that the lenti-expression of c-Jun could increases the expression of myelin, and downregulates the expression of Nogo-A under the CIMT on HCP mice. RESULT: (1) The beam walking test and grip test experiment results showed that compared with the control group, the HCP + nCIMT group's forelimb grasping ability and balance coordination ability were decreased (P < 0.05). (2) The results of Golgi staining, and transmission electron microscopy showed that the thickness of myelin sheath and the density of dendritic spines in the HCP + nCIMT group were lower than those in the control group (P < 0.05). Compared with the HCP + nCIMT group, the cerebral cortex myelin sheath thickness, dendrite spine density and nerve filament expression were increased in HCP + CIMT group (P < 0.05). (3) Immunofluorescence staining showed that the expression of Nogo-A in the cerebral cortex of the HCP + nCIMT group was higher than that of the HCP + CIMT group (P < 0.05). Compared with the HCP + CIMT group, the expression of Nogo-A in the HCP + LC + CIMT group was decreased and, in the HCP, + SC + CIMT group was significantly increased (P < 0.05). Compared with the HCP + nCIMT group, the expression of c-Jun in the control, HCP + CIMT, HCP + LC + nCIMT and HCP + LC + CIMT groups was significantly increased, and in the HCP + SC + CIMT was decreased (P < 0.05). (4) Real-time quantitative polymerase chain reaction (RT-qPCR) results showed that the expression level of miR-182-5p in the HCP + LC + CIMT group was more increased than that in the HCP + nCIMT group (P < 0.05). The expression level of miR-182-5p in the HCP + LC + CIMT group was higher than that in the HCP + LC + nCIMT group and the HCP + SC + CIMT group (P < 0.05). CONCLUSION: These data identified that CIMT might stimulate the remodeling of neurons and myelin in the motor cortex by partially inhibiting the c-Jun/miR-182-5p/Nogo-A pathway, thereby facilitating the grasping performance and balance function of HCP mice.


Asunto(s)
Parálisis Cerebral , MicroARNs , Corteza Motora , Ratones , Animales , Parálisis Cerebral/terapia , Proteínas Nogo , Hemiplejía/terapia , MicroARNs/genética
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