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1.
Phytomedicine ; 129: 155597, 2024 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-38643713

RESUMO

BACKGROUND: Sepsis-induced cardiac dysfunction (SICD) is a serious complication of sepsis that is associated with increased mortality. Ferroptosis has been reported in the SICD. TaoHe ChengQi decoction (THCQD), a classical traditional Chinese medicinal formula, has multiple beneficial pharmacological effects. The potential effects of THCQD on the SICD remain unknown. PURPOSE: To investigate the effect of THCQD on SICD and explore whether this effect is related to the regulation of myocardial ferroptosis through nuclear factor erythroid 2-related factor 2 (Nrf2) activation. METHODS: We induced sepsis in a mouse model using cecal ligation and puncture (CLP) and administered THCQD (2 and 4 g/kg) and dexamethasone (40 mg/kg). Mice mortality was recorded and survival curves were plotted. Echocardiography, hematoxylin and eosin staining, and analysis of serum myocardial injury markers and inflammatory factors were used to evaluate cardiac pathology. Myocardial ferroptosis was detected by quantifying specific biomarker content and protein levels. Through HPLC-Q-Exactive-MS analysis, we identified the components of the THCQD. Network pharmacology analysis and Cellular Thermal Shift Assay (CETSA) were utilized to predict the targets of THCQD for treating SICD. We detected the expression of Nrf2 using Western blotting or immunofluorescence. An RSL3-induced ferroptosis model was established using neonatal rat cardiomyocytes (NRCMs) to further explore the pharmacological mechanism of THCQD. In addition to measuring cell viability, we observed changes in NRCM mitochondria using electron microscopy and JC-1 staining. NRF2 inhibitor ML385 and Nrf2 knockout mice were used to validate whether THCQD exerted protective effects against SICD through Nrf2-mediated ferroptosis signaling. RESULTS: THCQD reduced mortality in septic mice, protected against CLP-induced myocardial injury, decreased systemic inflammatory response, and prevented myocardial ferroptosis. Network pharmacology analysis and CETSA experiments predicted that THCQD may protect against SICD by activating the Nrf2 signaling pathway. Western blotting and immunofluorescence showed that THCQD activated Nrf2 in cardiac tissue. THCQDs consistently mitigated RSL3-induced ferroptosis in NRCM, which is related to Nrf2. Furthermore, the pharmacological inhibition of Nrf2 and genetic Nrf2 knockout partially reversed the protective effects of THCQD on SICD and ferroptosis. CONCLUSION: The effect of THCQD on SICD was achieved by activating Nrf2 and its downstream pathways.

2.
Ageing Res Rev ; 96: 102286, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38561044

RESUMO

Chemokines and their corresponding receptors play crucial roles in orchestrating inflammatory and immune responses, particularly in the context of pathological conditions disrupting the internal environment. Among these receptors, CCR5 has garnered considerable attention due to its significant involvement in the inflammatory cascade, serving as a pivotal mediator of neuroinflammation and other inflammatory pathways associated with various diseases. However, a notable gap persists in comprehending the intricate mechanisms governing the interplay between CCR5 and its ligands across diverse and intricate inflammatory pathologies. Further exploration is warranted, especially concerning the inflammatory cascade instigated by immune cell infiltration and the precise binding sites within signaling pathways. This study aims to illuminate the regulatory axes modulating signaling pathways in inflammatory cells by providing a comprehensive overview of the pathogenic processes associated with CCR5 and its ligands across various disorders. The primary focus lies on investigating the pathomechanisms associated with CCR5 in disorders related to neuroinflammation, alongside the potential impact of aging on these processes and therapeutic interventions. The discourse culminates in addressing current challenges and envisaging potential future applications, advocating for innovative research endeavors to advance our comprehension of this realm.


Assuntos
Doenças Neuroinflamatórias , Receptores CCR5 , Humanos , Receptores CCR5/metabolismo , Transdução de Sinais
3.
Adv Healthc Mater ; : e2304254, 2024 Apr 09.
Artigo em Inglês | MEDLINE | ID: mdl-38593989

RESUMO

In obstructive airway diseases such as asthma and chronic obstructive pulmonary disease (COPD), the extracellular matrix (ECM) protein amount and composition of the airway smooth muscle (ASM) is often remodelled, likely altering tissue stiffness. The underlying mechanism of how human ASM cell (hASMC) mechanosenses the aberrant microenvironment is not well understood. Physiological stiffnesses of the ASM were measured by uniaxial compression tester using porcine ASM layers under 0, 5 and 10% longitudinal stretch above in situ length. Linear stiffness gradient hydrogels (230 kPa range) were fabricated and functionalized with ECM proteins, collagen I (ColI), fibronectin (Fn) and laminin (Ln), to recapitulate the above-measured range of stiffnesses. Overall, hASMC mechanosensation exhibited a clear correlation with the underlying hydrogel stiffness. Cell size, nuclear size and contractile marker alpha-smooth muscle actin (αSMA) expression showed a strong correlation to substrate stiffness. Mechanosensation, assessed by Lamin-A intensity and nuc/cyto YAP, exhibited stiffness-mediated behaviour only on ColI and Fn-coated hydrogels. Inhibition studies using blebbistatin or Y27632 attenuated most mechanotransduction-derived cell morphological responses, αSMA and Lamin-A expression and nuc/cyto YAP (blebbistatin only). This study highlights the interplay and complexities between stiffness and ECM protein type on hASMC mechanosensation, relevant to airway remodelling in obstructive airway diseases.

4.
Ultramicroscopy ; 262: 113962, 2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38642481

RESUMO

Ewald sphere curvature correction, which extends beyond the projection approximation, stretches the shallow depth of field in cryo-EM reconstructions of thick particles. Here we show that even for previously assumed thin particles, reconstruction artifacts which we refer to as ghosts can appear. By retrieving the lost phases of the electron exitwaves and accounting for the first Born approximation scattering within the particle, we show that these ghosts can be effectively eliminated. Our simulations demonstrate how such ghostbusting can improve reconstructions as compared to existing state-of-the-art software. Like ptychographic cryo-EM, our Ghostbuster algorithm uses phase retrieval to improve reconstructions, but unlike the former, we do not need to modify the existing data acquisition pipelines.

5.
BMC Plant Biol ; 24(1): 205, 2024 Mar 20.
Artigo em Inglês | MEDLINE | ID: mdl-38509465

RESUMO

BACKGROUND: Gynostemma pentaphyllum, an ancient Chinese herbal medicine, serves as a natural source of gypenosides with significant medicinal properties. Basic helix-loop-helix (bHLH) transcription factors play pivotal roles in numerous biological processes, especially in the regulation of secondary metabolism in plants. However, the characteristics and functions of the bHLH genes in G. pentaphyllum remain unexplored, and their regulatory role in gypenoside biosynthesis remains poorly elucidated. RESULTS: This study identified a total of 111 bHLH members in G. pentaphyllum (GpbHLHs), categorizing them into 26 subgroups based on shared conserved motif compositions and gene structures. Collinearity analysis illustrated that segmental duplications predominately lead to the evolution of GpbHLHs, with most duplicated GpbHLH gene pairs undergoing purifying selection. Among the nine gypenoside-related GpbHLH genes, two GpbHLHs (GpbHLH15 and GpbHLH58) were selected for further investigation based on co-expression analysis and functional prediction. The expression of these two selected GpbHLHs was dramatically induced by methyl jasmonate, and their nuclear localization was confirmed. Furthermore, yeast one-hybrid and dual-luciferase assays demonstrated that GpbHLH15 and GpbHLH58 could bind to the promoters of the gypenoside biosynthesis pathway genes, such as GpFPS1, GpSS1, and GpOSC1, and activate their promoter activity to varying degrees. CONCLUSIONS: In conclusion, our findings provide a detailed analysis of the bHLH family and valuable insights into the potential use of GpbHLHs to enhance the accumulation of gypenosides in G. pentaphyllum.


Assuntos
Gynostemma , Extratos Vegetais , Gynostemma/genética , Gynostemma/química , Gynostemma/metabolismo , Extratos Vegetais/química , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo
6.
J Orthop ; 54: 46-50, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38524364

RESUMO

Background: Tourniquet use during total knee arthroplasty (TKA) reduces bleeding which optimises bone-cement interface for prosthesis stability and improves surgical field visualisation. However, prolonged usage can lead to complications and poorer outcomes. Some surgeons advocate for intermittent tourniquet application. Limited literature exists for patients with high body mass index (BMI). This study aims to compare the outcomes of intermittent tourniquet (IT) to throughout tourniquet (TT) use among obese patients undergoing primary TKA for knee osteoarthritis. Methods: This was a retrospective cohort study. In the TT group, tourniquet was inflated from the beginning and released once the bone cement has hardened. In the IT group, tourniquet was inflated at the beginning, released after initial incision and haemostasis, then inflated again during cementation. Tourniquet was released once the bone cement had set. Categorical outcome measures were analysed using Chi-squared or Fisher's exact test. T-test or Kruskal-Wallis test were used for continuous data. Results: When comparing IT to TT among patients with BMI≥30 (IT n = 48, TT n = 47), the mean duration of surgery was shorter in the TT group (p < 0.05). The difference in haemoglobin drop between the two groups was not statistically significant from post-operative day three onwards. There was no difference in transfusion rate (p > 0.05). ROM was greater in the IT group up to three weeks post-operatively (p < 0.05). When comparing patients with BMI <30 (n = 71) and BMI≥30 (n = 48) with IT use, there was no statistically significant difference in ROM and LOS. Conclusion: Patients with BMI≥30 in the IT group had greater ROM in the initial post-operative period. Although operative time and blood loss were greater among the IT group, there was no difference in transfusion rate. Outcomes of TKA performed with IT were similar for patients with BMI≥30 and BMI <30. The authors recommend intermittent tourniquet use during TKA for patients with BMI≥30. Level of evidence: 3.

7.
Ying Yong Sheng Tai Xue Bao ; 35(1): 255-267, 2024 Jan.
Artigo em Chinês | MEDLINE | ID: mdl-38511463

RESUMO

The optimization of production-living-ecology (PLE) space is an important basis for promoting regional high-quality development. Taking the Dongting Lake Eco-economic Zone as an example, from the perspective of improving the comprehensive benefits of the development and protection of the PLE space, we coupled the GMOP-FLUS model, and proposed an optimization method combining the scenario configuration and the bottom line protection of the PLE space. We compared the three optimization scenarios (economic optimization scenario, ecological optimization scenario, and multi-objective optimization scenario), and coordinated the conflict areas of two lines to clarify the comprehensive optimization scheme of the PLE space in the Dongting Lake Eco-economic Zone. The results showed the characteristics of increasing production space and living space and decreasing ecological space from 2010 to 2020, resulting in the partial loss of land ecological and environmental benefits. Under the economic optimization scenario, the ecological optimization scenario promoted the rapid growth of regional economy but damaged regional ecological security. The ecological optimization scenario inhibited regional economic development. The multi-objective optimization scenario led to improvement of economic and ecological benefits of the PLE space, which increased by 2.0% and 1.3%, respectively. The multi-objective optimization scenario was the best optimization scenario among the three scenarios. By superimposing the best scenario and the two-line conflict regional coordination results, we obtained the comprehensive optimization scheme for 2030. The production space, living space, and ecological space areas of the scheme were 25777.18, 2062.94, and 32552.68 km2, respectively. Based on the natural and social conditions, combining the comprehensive optimization scheme, we put forward different control suggestions for each type of PLE space. Our results could provide reference for the rational formulation of territorial spatial planning and the formulation of policies for the coordinated development of ecological environment and social economy in the Dongting Lake Eco-economic Zone.


Assuntos
Conservação dos Recursos Naturais , Ecologia , Conservação dos Recursos Naturais/métodos , Lagos , Desenvolvimento Econômico , China , Ecossistema
8.
Sci Rep ; 14(1): 7364, 2024 03 28.
Artigo em Inglês | MEDLINE | ID: mdl-38548903

RESUMO

Esophagogastric variceal bleeding (EVB) is one of the common digestive system emergencies with poor prognosis and high rate of rebleeding after treatment. To explore the effects of endoscopic therapy and drug therapy on the prognosis and rebleeding of patients with EVB, and then select better treatment methods to effectively improve the prognosis. From January 2013 to December 2022, 965 patients with EVB who were hospitalized in gastroenterology Department of the 940 Hospital of Joint Logistic Support Forces of PLA were retrospectively analyzed. Patients were divided into endoscopic treatment group (ET, n = 586) and drug treatment group (DT, n = 379). Propensity score matching (PSM) analysis was performed in both groups, and the general information, efficacy and length of hospital stay were recorded. The patients were followed up for 3 months after bleeding control to determine whether rebleeding occurred. There were 286 cases in each group after PSM. Compared with DT group, ET had higher treatment success rate (P < 0.001), lower rebleeding rate (P < 0.001), lower mortality rate within 3 months, and no significant difference in total hospital stay (P > 0.05). Compared with drug therapy, endoscopic treatment of EVB has short-term efficacy advantages, and can effectively reduce the incidence of rebleeding and mortality within 3 months.


Assuntos
Varizes Esofágicas e Gástricas , Humanos , Varizes Esofágicas e Gástricas/complicações , Varizes Esofágicas e Gástricas/terapia , Estudos Retrospectivos , Hemorragia Gastrointestinal/etiologia , Hemorragia Gastrointestinal/terapia , Endoscopia/efeitos adversos , Prognóstico , Resultado do Tratamento , Recidiva
9.
Chem Biol Interact ; 394: 110978, 2024 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-38552766

RESUMO

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by the accumulation of amyloid-ß (Aß) protein aggregates, leading to synaptic dysfunction and neuronal cell death. In this study, we used a comprehensive approach encompassing in vitro assays, computational analyses, and an in vivo Caenorhabditis elegans model to evaluate the inhibitory effects of various xanthones, focusing on Garcinone D (GD), on Aß42 oligomer formation. Dot blot analysis revealed concentration-dependent responses among xanthones, with GD consistently inhibiting Aß42 oligomer formation at low concentrations (0.1 and 0.5 µM, inhibitions of 84.66 ± 2.25% and 85.06 ± 6.57%, respectively). Molecular docking and dynamics simulations provided insights into the molecular interactions between xanthones and Aß42, highlighting the disruption of key residues involved in Aß42 aggregation. The neuroprotective potential of GD was established using transgenic C. elegans GMC101, with substantial delays in paralysis reported at higher concentrations. Our findings show that GD is a potent suppressor of Aß42 oligomer formation, suggesting its potential as a therapeutic candidate for AD. The concentration-dependent effects observed in both in vitro and in vivo models underscore the need for nuanced dose-response assessments. These findings contribute novel insights into the therapeutic landscape of xanthones against AD, emphasizing the multifaceted potential of GD for further translational endeavors in neurodegenerative disorder research.

10.
Reprod Sci ; 2024 Mar 07.
Artigo em Inglês | MEDLINE | ID: mdl-38453773

RESUMO

This study aims to investigate the effect and mechanism of dehydroepiandrosterone (DHEA) on diminished ovarian reserve (DOR) by modulating the AMPK-SIRT1 signaling and mitophagy in rats. Three-month-old female Sprague-Dawley (SD) rats were randomized and injected intraperitoneally with sesame oil as the control or deoxyvinylcyclohexene (VCD) to induce DOR. The VCD-injected rats were randomized and injected subcutaneously with vehicle as the model group or with DHEA for 21 days as the DHEA group. After being identified in proestrus, rat blood samples were collected to prepare serum samples, and their ovarian tissues were dissected. Compared with the controls, significantly lower serum estradiol (E2), anti-Müllerian hormone (AMH), and inhibin B (IHNB) and higher follicle-stimulating hormone (FSH) and luteinizing hormone (LH) levels were detected in the model group (DOR rats). The model group of rats displayed an increase in follicular atresia and a decrease in ovarian volume and the number of growing follicles and corpus luteum, accompanied by increased frequency of oocyte apoptosis and reduced levels of mitochondrial function. Furthermore, significantly higher levels of the AMPK-SIRT1 signaling and mitophagy were observed in the ovaries of rats in the model group. In contrast, treatment with DHEA significantly ameliorated the hormone disorder and morphological changes in the ovaries, reduced the frequency of apoptotic oocytes, and improved mitochondrial function in the ovaries of DOR rats. Mechanistically, DHEA treatment significantly attenuated the AMPK-SIRT1 signaling and mitophagy in the ovaries of DOR rats. DHEA treatment reduced the severity of DOR and enhanced ovarian reserve function by attenuating the AMPK-SIRT1 signaling and mitophagy in the ovaries of rats.

11.
Artigo em Inglês | MEDLINE | ID: mdl-38321265

RESUMO

PURPOSE: Decreased ovarian reserve function is mainly characterized by female endocrine disorders and fertility decline. Follicular fluid (FF) exosomal microRNAs (miRNAs) have been shown to regulate the function of granulosa cells (GCs). The present study explored differentially expressed miRNAs (DEmiRNAs) in patients with diminished ovarian reserve (DOR). METHODS: FF was collected from 12 DOR patients and 12 healthy controls. DEmiRNAs between the two groups were identified and analyzed using high-throughput sequencing technology and validated by real-time quantitative PCR (RT-qPCR). RESULTS: A total of 592 DEmiRNAs were identified using high-throughput miRNA sequencing, of which 213 were significantly upregulated and 379 were significantly downregulated. The sequencing results were further validated by RT-qPCR. These DEmiRNA target genes were mainly involved in the cancer pathway, phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway, regulation of actin cytoskeleton signaling pathway, and biological processes related to protein binding, nucleoplasm, cytoplasm, and cell membrane. CONCLUSION: FF exosomal miRNAs are significantly differentially expressed in DOR patients versus non-DOR patients, underscoring their crucial role in regulating the pathogenesis of DOR.

12.
Brain Imaging Behav ; 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38316730

RESUMO

Pain is a pervasive symptom in lung cancer patients during the onset of the disease. This study aims to investigate the connectivity disruption patterns of the whole-brain functional network in lung cancer patients with cancer pain (CP+). We constructed individual whole-brain, region of interest (ROI)-level functional connectivity (FC) networks for 50 CP+ patients, 34 lung cancer patients without pain-related complaints (CP-), and 31 matched healthy controls (HC). Then, a ROI-based FC analysis was used to determine the disruptions of FC among the three groups. The relationships between aberrant FCs and clinical parameters were also characterized. The ROI-based FC analysis demonstrated that hypo-connectivity was present both in CP+ and CP- patients compared to HC, which were particularly clustered in the somatomotor and ventral attention, frontoparietal control, and default mode modules. Notably, compared to CP- patients, CP+ patients had hyper-connectivity in several brain regions mainly distributed in the somatomotor and visual modules, suggesting these abnormal FC patterns may be significant for cancer pain. Moreover, CP+ patients also showed increased intramodular and intermodular connectivity strength of the functional network, which could be replicated in cancer stage IV and lung adenocarcinoma. Finally, abnormal FCs within the prefrontal cortex and somatomotor cortex were positively correlated with pain intensity and pain duration, respectively. These findings suggested that lung cancer patients with cancer pain had disrupted connectivity in the intrinsic brain functional network, which may be the underlying neuroimaging mechanisms.

14.
Nanoscale ; 16(8): 4014-4024, 2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38349080

RESUMO

Immobilizing metal nanoparticles on a support is crucial for catalysts' stability and spatial distribution. MXenes are promising substrates for in situ growth engineering of various electrocatalysts owing to their merits. A stronger binding capacity can be achieved between the in situ-fabricated catalysts and MXenes compared to a common physical combination. Thus, synergistically utilizing morphology modulation, composition optimization, and the interfacial interaction between metal catalysts and supports will maximize the electrocatalytic activity. However, most reported in situ-formed catalysts on MXenes result in solid 0D nanoparticles and in situ growth of nanoalloy catalysts on MXenes with a precisely controlled morphology is still lacking. Herein, nanodendritic PdNi alloys are in situ grown on nitrogen-doped V2CTx, serving as efficient electrocatalysts toward the hydrogen evolution reaction (HER). Thanks to the synergistic effect of the unique nanodendritic structure of PdNi, the merits of N-TBA-V2CTx nanosheets, and the strong metal-support interaction between the PdNi and the N-TBA-V2CTx support, the in situ-formed Pd58Ni42/N-TBA-V2CTx electrocatalyst shows excellent HER performance with an ultralow overpotential of 44.1 mV to achieve 10 mA cm-2 and a lowest Tafel slope of 39.4 mV dec-1, which outperforms Pd58Ni42/TBA-V2CTx, Pd58Ni42, and Pd/C. Remarkably, the Pd58Ni42/N-TBA-V2CTx catalyst can maintain 92.3% of its initial activity even after 50 h of continuous operation.

15.
Mol Biotechnol ; 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38305844

RESUMO

Aptamers, as a kind of small-molecule nucleic acid, have attracted much attention since their discovery. Compared with biological reagents such as antibodies, aptamers have the advantages of small molecular weight, low immunogenicity, low cost, and easy modification. At present, aptamers are mainly used in disease biomarker discovery, disease diagnosis, treatment, and targeted drug delivery vectors. In the process of screening and optimizing aptamers, it is found that there are still many problems need to be solved such as the design of the library, optimization of screening conditions, the truncation of screened aptamer, and the stability and toxicity of the aptamer. In recent years, the incidence of liver-related diseases is increasing year by year and the treatment measures are relatively lacking, which has attracted the people's attention in the application of aptamers in liver diseases. This article mainly summarizes the research status of aptamers in disease diagnosis and treatment, especially focusing on the application of aptamers in liver diseases, showing the crucial significance of aptamers in the diagnosis and treatment of liver diseases, and the use of Discovery Studio software to find the binding target and sequence of aptamers, and explore their possible interaction sites.

17.
Crit Rev Biotechnol ; : 1-21, 2024 Jan 21.
Artigo em Inglês | MEDLINE | ID: mdl-38246753

RESUMO

Stress tolerance is a vital attribute for all living beings to cope with environmental adversities. IrrE (also named PprI) from Deinococcus radiodurans enhances resistance to extreme radiation stress by functioning as a global regulator, mediating the transcription of genes involved in deoxyribonucleic acid (DNA) damage response (DDR). The expression of IrrE augmented the resilience of various species to heat, radiation, oxidation, osmotic stresses and inhibitors, encompassing bacterial, fungal, plant, and mammalian cells. Moreover, IrrE was employed in a global regulator engineering strategy to broaden its applications in stress tolerance. The regulatory impacts of heterologously expressed IrrE have been investigated at the molecular and systems level, including the regulation of genes, proteins, modules, or pathways involved in DNA repair, detoxification proteins, protective molecules, native regulators and other aspects. In this review, we discuss the regulatory role and mechanism of IrrE in the antiradiation response of D. radiodurans. Furthermore, the applications and regulatory effects of heterologous expression of IrrE to enhance abiotic stress tolerance are summarized in particular.

18.
Commun Chem ; 7(1): 7, 2024 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-38182798

RESUMO

Halogenation of pyrrole requires strong electrophilic reagents and often leads to undesired polyhalogenated products. Biocatalytic halogenation is a highly attractive approach given its chemoselectivity and benign reaction conditions. While there are several reports of enzymatic phenol and indole halogenation in organic synthesis, corresponding reports on enzymatic pyrrole halogenation have been lacking. Here we describe the in vitro functional and structural characterization of PrnC, a flavin-dependent halogenase that can act on free-standing pyrroles. Computational modeling and site mutagenesis studies identified three key residues in the catalytic pocket. A moderate resolution map using single-particle cryogenic electron microscopy reveals PrnC to be a dimer. This native PrnC can halogenate a library of structurally diverse pyrrolic heterocycles in a site-selective manner and be applied in the chemoenzymatic synthesis of a chlorinated analog of the agrochemical fungicide Fludioxonil.

19.
Nat Commun ; 15(1): 389, 2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38195598

RESUMO

Structural biology efforts using cryogenic electron microscopy are frequently stifled by specimens adopting "preferred orientations" on grids, leading to anisotropic map resolution and impeding structure determination. Tilting the specimen stage during data collection is a generalizable solution but has historically led to substantial resolution attenuation. Here, we develop updated data collection and image processing workflows and demonstrate, using multiple specimens, that resolution attenuation is negligible or significantly reduced across tilt angles. Reconstructions with and without the stage tilted as high as 60° are virtually indistinguishable. These strategies allowed the reconstruction to 3 Å resolution of a bacterial RNA polymerase with preferred orientation, containing an unnatural nucleotide for studying novel base pair recognition. Furthermore, we present a quantitative framework that allows cryo-EM practitioners to define an optimal tilt angle during data acquisition. These results reinforce the utility of employing stage tilt for data collection and provide quantitative metrics to obtain isotropic maps.


Assuntos
Benchmarking , Sistemas Computacionais , Microscopia Crioeletrônica , Anisotropia , Coleta de Dados
20.
Redox Biol ; 70: 103024, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38232458

RESUMO

Due to the cardiotoxicity of doxorubicin (DOX), its clinical application is limited. Lipid peroxidation caused by excessive ferrous iron is believed to be a key molecular mechanism of DOX-induced cardiomyopathy (DIC). Dexrazoxane (DXZ), an iron chelator, is the only drug approved by the FDA for reducing DIC, but it has many side effects and cannot be used as a preventive drug in clinical practice. Single-nucleus RNA sequencing (snRNA-seq) analysis identified myocardial and epithelial cells that are susceptible to DOX-induced ferroptosis. The glutathione peroxidase 4 (GPX4) activator selenomethione (SeMet) significantly reduced polyunsaturated fatty acids (PUFAs) and oxidized lipid levels in vitro. Consistently, SeMet significantly decreased DOX-induced lipid peroxidation in H9C2 cells and mortality in C57BL/6 mice compared to DXZ, ferrostatin-1, and normal saline. SeMet can effectively reduce serum markers of cardiac injury in C57BL/6 mice and breast cancer patients. Depletion of the GPX4 gene in C57BL/6 mice resulted in an increase in polyunsaturated fatty acid (PUFA) levels and eliminated the protective effect of SeMet against DIC. Notably, SeMet exerted antitumor effects on breast cancer models with DOX while providing cardiac protection for the same animal without detectable toxicities. These findings suggest that pharmacological activation of GPX4 is a valuable and promising strategy for preventing the cardiotoxicity of doxorubicin.


Assuntos
Neoplasias da Mama , Cardiomiopatias , Humanos , Camundongos , Animais , Feminino , Fosfolipídeo Hidroperóxido Glutationa Peroxidase , Cardiotoxicidade/etiologia , Camundongos Endogâmicos C57BL , Cardiomiopatias/induzido quimicamente , Cardiomiopatias/tratamento farmacológico , Cardiomiopatias/patologia , Doxorrubicina/efeitos adversos , Ácidos Graxos Insaturados
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