Quantitative Transmission Electron Microscopy Research Articles

Gene Expression, Morphology, and Electrophysiology During the Dynamic Development of Human Induced Pluripotent Stem Cell-Derived Atrial- and Ventricular-Like Cardiomyocytes.

Gene expression, morphology, and electrophysiological combination are essential for assessing the dynamic development of human induced pluripotent stem cell-derived atrial- and ventricular-like cardiomyocytes (iPS-AM and iPS-VM, respectively). For iPS-AM/VM differentiation, we performed the small molecule-based temporal modulation of the retinoic acid and bone morphogenetic protein signaling pathways. We investigated the gene expression and morphology using immunofluorescence, quantitative real-time polymerase chain reaction, flow cytometry, and transmission electron microscopy as well as registered electrophysiological functions using a whole-cell patch clamp on days 20, 30, and 60 post-differentiations. Pan-cardiomyocyte marker, including troponin T2 (TNNT2) and alpha-actinin-2 (ACTN2), expressions increased both in iPS-AMs and iPS-VMs. Similarly, the mRNA expression of both iPS-AM-specific markers, ie, natriuretic peptide A (NPPA), myosin light chain 7 (MYL7), and K+ channel Kir3.4 (KCNJ5), and iPS-VM-specific markers, ie, gap junction α-1 (GJA1), myosin light chain 2 (MYL2), and alpha-1-subunit of a voltage-dependent L-type calcium channel (CACNA1C), increased from 0 to 20 days, and then decreased from 30 to 60 days. Concerning morphology, cardiac troponin-T (cTnT) arrangement was progressively organized and developed from a disorderly myofibrillar distribution to an organized sarcomere pattern both in iPS-AMs and iPS-VMs. Mitochondrial numbers gradually increased and those of lipid droplets decreased during dynamic development. Regarding physiological function, the resting and action potential amplitudes remained statistically indifferent in both cell types, and the action potential duration was prolonged during the development. IPS-AMs/VMs displayed dynamic development concerning their gene expression, morphology, and electrophysiological function. The discoveries of this study could provide novel insights into heart development and encourage further research.

Based on Virtual Screening and Simulation Exploring the Mechanism of Plant-Derived Compounds with PINK1 to Postherpetic Neuralgia.

Accumulating evidence strongly supports that PINK1 mutation can mediate mitochondrial autophagy dysfunction in dopaminergic neurons. This study was conducted to determine the role of PINK1 in the pathogenesis of postherpetic neuralgia (PHN) and find new targets for its treatment. A rigorous literature review was conducted to identify 2801 compounds from more than 200 plants in Asia. Virtual screening was used to shortlist the compounds into 20 groups based on their binding energies. MM/PBSA was used to further screen the compound dataset, and vitexin, luteoloside, and 2'-deoxyadenosine-5'-monophosphate were found to have a score of - 59.439, - 52.421, and - 47.544kcal/mol, respectively. Pain behavioral quantification, enzyme-linked immunosorbent assay, quantitative polymerase chain reaction, western blotting, and transmission electron microscopy were used to confirm the effective mechanism. Vitexin had the most significant therapeutic effect on rats with PHN followed by luteoloside; 2'-deoxyadenosine-5'-monophosphate had no significant effect. Our findings suggested that vitexin could alleviate PHN by regulating mitochondrial autophagy through PINK1.

Curcumin simultaneously improves mitochondrial dynamics and myocardial cell bioenergy after sepsis via the SIRT1-DRP1/PGC-1α pathway

Septic cardiomyopathy (SCM) is associated with an imbalance in mitochondrial quality and high mortality rates, with no effective treatment developed to date. Curcumin provides antioxidant, anti-inflammatory, cardiovascular, and mitochondrial protection. However, curcumin has not been confirmed to improve cardiac dysfunction in sepsis. We hypothesized that curcumin can reduce abnormal inflammatory responses by improving mitochondrial function as a novel mechanism to improve SCM. To explore this hypothesis, we used an in vivo male C57BL/6 mouse sepsis model and an in vitro model of lipopolysaccharide-stimulated HL-1 cells. The effects of curcumin on sepsis-induced cardiac dysfunction, inflammatory responses, and mitochondrial quality of cardiac cells were observed using quantitative polymerase chain reaction, western blotting, echocardiography, and transmission electron microscopy. Curcumin activated sirtuin 1 (SIRT1); increased expression of the mitochondrial biogenesis-related genes Pgc1α, Tfam, and Nrf2; reduced dynamin-related protein 1 translocation from the cytoplasm to mitochondria; and restored the mitochondrial morphology and function in cardiac cells. Accordingly, curcumin protected heart function after septic shock and alleviated the effects of SCM. SIRT1 knockdown reversed the protective effects of curcumin on mitochondria. Therefore, curcumin promotes mitochondrial biogenesis and inhibits mitochondrial fragmentation by activating SIRT1, thereby improving the mitochondrial quality and reducing oxidative stress in cardiomyocytes and sepsis-induced cardiac dysfunction. These findings provide new evidence supporting the use of curcumin to treat SCM.

Extracellular Sombrero Vesicles are Hallmarks of Eosinophilic Cytolytic Degranulation in Tissue Sites of Human Diseases.

Eosinophil sombrero vesicles (EoSVs) are large tubular carriers resident in the cytoplasm of human eosinophils, identifiable by transmission electron microscopy (TEM), and important for immune mediator transport. Increased EoSV formation occurs in activated eosinophils in vitro and in vivo. In tissue sites of eosinophilic cytolytic inflammation, extracellular EoSVs are noted, but their frequency and significance in eosinophil-associated diseases (EADs) remain unclear. Here, we performed comprehensive quantitative TEM analyses and electron tomography to investigate the numbers, density, integrity, and three-dimensional (3D) structure of EoSVs in different biopsy tissues from five prototypic EADs (eosinophilic chronic rhinosinusitis/nasal sinuses, ulcerative colitis/intestines, hypereosinophilic syndrome/skin, dermatitis/skin, and schistosomiasis/rectum). The morphology of extracellular EoSVs was also compared with that of cytoplasmic EoSVs, isolated by subcellular fractionation from peripheral blood eosinophils. We demonstrated that: i) eosinophil cytolysis, releasing intact EoSVs and membrane-bound granules, is a consistent event in all EADs; ii) EoSVs persist intact even after complete disintegration of all cell organelles, except granules (late cytolysis); iii) the EoSV population, composed of elongated, curved, and typical sombreros, and the EoSV 3D architecture, diameter, and density remain unchanged in the extracellular matrix; iv) free EoSVs closely associate with extracellular granules; and v) free EoSVs also associate with externalized chromatin during eosinophil ETosis. Remarkably, EoSVs appeared on the surface of other cells like plasma cells. Thus, eosinophil cytolysis/ETosis can secrete intact EoSVs, alongside granules, in inflamed tissues of EADs, potentially serving as propagators of eosinophil immune responses post-cell death.

Eosinophil activation during immune responses: an ultrastructural view with an emphasis on viral diseases.

Eosinophils are cells of the innate immune system that orchestrate complex inflammatory responses. The study of the cell biology of eosinophils, particularly associated with cell activation, is of great interest to understand their immune responses. From a morphological perspective, activated eosinophils show ultrastructural signatures that have provided critical insights into the comprehension of their functional capabilities. Application of conventional transmission electron microscopy (TEM) in combination with quantitative assessments (quantitative TEM), molecular imaging (immunoEM), and three-dimensional (3D) electron tomography have generated important insights into mechanisms of eosinophil activation. This review explores a multitude of ultrastructural events taking place in eosinophils activated in vitro and in vivo as key players in allergic and inflammatory diseases, with an emphasis on viral infections. Recent progress in our understanding of biological processes underlying eosinophil activation, including in vivo mitochondrial remodeling, is discussed, and it can bring new thinking to the field.

Studies on the mechanisms of Helicobacter pylori inhibition by Syzygium aromaticum aqueous extract

BackgroundThe aqueous extract of the dried buds of Syzygium aromaticum (SAAE) have the potential to alleviate Helicobacter pylori infection, but the specific molecular mechanism has not been fully elucidated. PurposeThis study aimed to investigate the underlying mechanisms of SAAE on H. pylori pathogenicity. MethodsThe inhibitory kinetics and anti-H. pylori adhesive capacity assays were conducted to examine the effects of SAAE on the growth and adhesive capability of H. pylori. The H. pylori outer membrane vesicles (OMVs) were purified from the culture supernatant through high-speed centrifugation, filtration, and two rounds of ultracentrifugation. Their characteristics and protein composition were then identified using transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and qualitative proteomics study. Subsequently, the effect of SAAE on the pathogenicity of H. pylori OMVs was investigated using the Griess reagent assay, enzyme-linked immunosorbent assay (ELISA), quantitative proteomics study, TEM, and western blotting assay. ResultsSAAE exhibited inhibitory effects on H. pylori growth and adhesion. The isolated H. pylori OMVs showed particle size of 27∼242 nm and Zeta potential of -9.67 ± 0.53 mV. A total of 599 proteins were identified in the OMVs. Proteomics study indicated that the differential expressed proteins induced by OMVs with or without SAAE commonly enriched in P53 and autophagy pathways. Besides, SAAE counteracted the increased production of pro-inflammatory cytokines and attenuated the induction of cell autophagy caused by H. pylori OMVs. Furthermore, SAAE normalized the abnormal regulation of downstream targets (AIFM2 and IGFBP3) in the P53 signaling pathway caused by H. pylori OMVs. ConclusionSAAE can inhibit the growth and adhesion of H. pylori, reduce the inflammation and autophagy induced by H. pylori OMVs, and combated the abnormal regulation of P53 signaling pathway caused by H. pylori OMVs. These findings may help elucidate the mechanisms through which SAAE reduces the pathogenicity of H. pylori.

Atom counting based on Voronoi averaged STEM intensities using a crosstalk correction scheme

If quantitative scanning transmission electron microscopy is used for very precise thickness measurements with atomic resolution, it is commonly referred to as »atom counting«. Due to scattering and the finite probe extent the signal recorded in one atomic column is dependent not only on its own height but also on the height of its neighbours. Especially for thicker specimens this crosstalk effect can have significant impact on the measured intensity. If it is not appropriately accounted for in the evaluation, it can result in a deterioration of accuracy that impedes the possibility of actual atom counting. However, as the number of possible neighbour configurations can be excessively large, a comprehensive consideration of all in the evaluation reference is neigh impossible. This work proposes a method that allows for the a-posteriori reduction of crosstalk during the evaluation by algebraic means. Based on a parametric model, which is described in detail in the article, the crosstalk is expressed by an invertible matrix. Applying the inverted matrix to the measurement yields crosstalk corrected intensity values with very little computational effort. These can subsequently be evaluated by direct comparison to simple reference data. The working principle of the method is presented on the example of crystalline gold. The crosstalk parametrisation is found by fitting a model to sets of specifically created multislice simulations. The parameters are given for both aberration corrected and uncorrected STEM. Subsequently the abilities and potential of the technique are assessed in simulative studies on multiple model systems including gold nanoparticles. Overall a significant and robust improvement of the attainable precision can be demonstrated making the proposed method a promising tool for reference-based atom counting.

Effects of small pre-stretching on the microstructural evolution and strengthening of an Al–Cu–Mg–Ag alloy

Pre-stretching prior to aging is known to degrade the performance of Al–Cu–Mg–Ag alloys at elevated temperatures. In this work, small pre-stretching by 0.5% and 1.8% is selected to explore its potential influences on the microstructure and strengthening capacity of an Al–Cu–Mg–Ag alloy. The strength and microstructure of Al–Cu–Mg–Ag alloy are found to be sensitive to the pre-stretching. Even 0.5% pre-stretching can reduce the alloy strength by more than 10 MPa. Quantitative transmission electron microscopy (TEM) and atom probe tomography (APT) analysis indicate that this detrimental effect of pre-stretching on strength is directly associated with the suppressed Mg–Ag co-clustering, which greatly delays the Ω precipitation and induces a weaker strengthening effect. Quantitative calculation reveals that Mg–Ag co-clusters exhibit the greatest strengthening contribution to the yield strength of the underaged material because of its strongest cluster hardening, which is mainly originated from its order hardening capacity. As the pre-stretching increases from 0.5% to 1.8%, the θ coarsening is progressively intensified during exposing at 200 °C, accompanied by a gradual drop in the number density of Ω phase. Besides, the formation of a cubic σ phase is found to be considerably enhanced after exposing at 200 °C for 500h as the pre-stretching increases.

The dynamics and removal efficiency of antibiotic resistance genes by UV-LED treatment: An integrated research on single- or dual-wavelength irradiation

Antimicrobial resistance has gained increasing attention, because of the awareness of its potential health risks. Strategies for the removal of antibiotic resistance genes (ARGs) are urgently required. In the present study, UV-LEDs at wavelength of 265 and 285 nm were integrated at five conditions, including single 265 nm UV-LED, single 285 nm UV-LED, and combined 265 nm and 285 nm UV-LED at different intensities, to remove tet A, cat 1, and amp C. The ARGs removal efficiency, gene behavior, and possible cellular mechanism were analyzed using real-time quantitative PCR, flow cytometry, and transmission electron microscopy (TEM). The 265 nm UV-LED is more effective than the 285 nm UV-LED and their combinations in terms of ARGs control, in which 1.91, 1.71, and 1.45 log were removed for tet A, cat 1, and amp C, respectively, at a UV dosage of 500 mJ/cm2. The intracellular gene leakage was detected in all five UV-LED experiment scenarios even when the cell membrane damage was insignificant with the highest increase of 0.69 log ARGs. ROS was generated during the irradiation, and the ROS was strongly negative correlated with intracellular ARGs, which could promote the degradation and removal of ARGs. This study provides a new insight of intracellular ARGs removal, because direct irradiation, ROS oxidation, and leakage to the extracellular serve as the three main pathways under high-dosage UV-LED irradiation. Further research should be focused on the mechanism and optimization of UV technology with 265 nm UV-LED for ARG control.

On the role of Ag additions on the initial solute hardening and competitive precipitation of Al-Cu-Mg alloys

The initial solute clustering is known to significantly affect the subsequent precipitation of various strengthening precipitates that determine the mechanical properties of Al-Cu-Mg-Ag alloys. In this work, the influence of Ag variations on the initial cluster hardening and microstructure evolution of Al-Cu-Mg-Ag alloys is investigated by quantitative transmission electron microscopy (TEM), electron backscatter diffraction (EBSD) and atom probe tomography (APT) analysis. Our statistical data and calculation results indicate that the overwhelming Mg-Ag co-clustering by increasing Ag from 0.41 to 0.97 indeed enables a higher nucleation rate of Ω phase and contributes to a denser Ω precipitation generating a stronger age-hardening response at 180 ℃. Analysis of the contribution of individual precipitates to the yield strength highlights the positive role of increasing Ag on improving the cluster hardening capacity of Mg-Ag co-clusters by increasing its order hardening level. Compared with Cu-Mg co-clusters and GP zones, Mg-Ag co-clusters exhibit a greatest strengthening contribution to yield strength of the material as the bulk Ag content increases. Except for GP zones, Mg-Ag and Cu-Mg co-clusters prefer to exhibit a strong order hardening rather than modulus hardening in initially aged alloys. In addition, the average grain sizes, as well as the proportions of low angle grain boundaries (LAGBs) and high angle grain boundaries (HAGBs), reveal no distinct differences in both alloys, suggesting the independence of grain structure on the bulk Ag content.

Robust Local Thickness Estimation of Sub-Micrometer Specimen by 4D-STEM.

A quantitative four-dimensional scanning transmission electron microscopy (4D-STEM) imaging technique (q4STEM) for local thickness estimation across amorphous specimen such as obtained by focused ion beam (FIB)-milling of lamellae for (cryo-)TEM analysis is presented. This study is based on measuring spatially resolved diffraction patterns to obtain the angular distribution of electron scattering, or the ratio of integrated virtual dark and bright field STEM signals, and their quantitative evaluation using Monte Carlo simulations. The method is independent of signal intensity calibrations and only requires knowledge of the detector geometry, which is invariant for a given instrument. This study demonstrates that the method yields robust thickness estimates for sub-micrometer amorphous specimen using both direct detection and light conversion 2D-STEM detectors in a coincident FIB-SEM and a conventional SEM. Due to its facile implementation and minimal dose reauirements, it is anticipated that this method will find applications for in situ thickness monitoring during lamella fabrication of beam-sensitive materials.

On the origin of carrier localization in AlInAsSb digital alloy

We compared the photoluminescence (PL) properties of AlInAsSb digital alloy samples with different periods grown on GaSb (001) substrates by molecular beam epitaxy. Temperature-dependent S-shape behavior is observed and explained using a thermally activated redistribution model within a Gaussian distribution of localized states. There are two different mechanisms for the origin of the PL intensity quenching for the AlInAsSb digital alloy. The high-temperature activation energy E 1 is positively correlated with the interface thickness, whereas the low-temperature activation energy E 2 is negatively correlated with the interface thickness. A quantitative high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) study shows that the interface quality improves as the interface thickness increases. Our results confirm that E 1 comes from carrier trapping at a state in the InSb interface layer, while E 2 originates from the exciton binding energy due to the roughness of the AlAs interface layer.

Quantitative Scanning Transmission Electron Microscopy for Materials Science: Imaging, Diffraction, Spectroscopy, and Tomography

Scanning transmission electron microscopy (STEM) is one of the most powerful characterization tools in materials science research. Due to instrumentation developments such as highly coherent electron sources, aberration correctors, and direct electron detectors, STEM experiments can examine the structure and properties of materials at length scales of functional devices and materials down to single atoms. STEM encompasses a wide array of flexible operating modes, including imaging, diffraction, spectroscopy, and 3D tomography experiments. This review outlines many common STEM experimental methods with a focus on quantitative data analysis and simulation methods, especially those enabled by open source software. The hope is to introduce both classic and new experimental methods to materials scientists and summarize recent progress in STEM characterization. The review also discusses the strengths and weaknesses of the various STEM methodologies and briefly considers promising future directions for quantitative STEM research.

N-3 PUFA Promotes Ferroptosis in PCOS GCs by Inhibiting YAP1 through Activation of the Hippo Pathway.

Polycystic ovary syndrome (PCOS) is an endocrine disorder characterized by hyperandrogenemia with multiple suspended sinus follicles, thickened cortical tissue, and excessive proliferation of ovarian granulosa cells that severely affects the fertility and quality of life of women. The addition of n-3 PUFA to the diet may slightly reduce body weight and greatly alleviate disturbed blood hormone levels in PCOS mice. We treated KGN as a cell model for n-3 PUFA addition and showed that n-3 PUFA inhibited the proliferation of GCs and promoted ferroptosis in ovarian granulosa cells. We used CCK-8, fluorescence quantitative transmission electron microscopy experiments and ferroptosis marker gene detection and other methods. Furthermore, n-3 PUFA was found to promote YAP1 exocytosis by activating Hippo and weakening the cross-talk between YAP1 and Nrf2 by activating the Hippo signaling pathway. In this study, we found that n-3 PUFA inhibited the over proliferation of granulosa cells in ovarian follicles by activating Hippo, promoting YAP1 exocytosis, weakening the cross-talk between YAP1 and Nrf2, and ultimately activating the ferroptosis sensitivity of ovarian granulosa cells. We demonstrate that n-3 PUFA can alleviate the hormonal and estrous cycle disorder with PCOS by inhibiting the YAP1-Nrf2 crosstalk that suppresses over proliferating ovarian granulosa cells and promotes iron death in GCs. These findings reveal the molecular mechanisms by which n-3 PUFA attenuates PCOS and identify YAP1-Nrf2 as a potential therapeutic target for regulation granulosa cells in PCOS.

Inhibition of Autophagy Maintains ESC Pluripotency and Inhibits Primordial Germ Cell Formation in Chickens.

Autophagy plays an important role in the pluripotency and differentiation of stem cells. Transcriptome data showed that the autophagy genes MAP1LC3A and MAP1LC3B were significantly upregulated in primordial germ cells (PGCs). The Kyoto Encyclopedia of Genes and Genome (KEGG) results showed that the lysosome signaling pathway, which is related to autophagy, was significantly enriched in PGCs. Quantitative RT-PCR, western blotting, and transmission electron microscopy (TEM) results showed that autophagy was expressed in both embryonic stem cells (ESCs) and PGCs but was significantly activated in PGCs. To explore the role of autophagy in the differentiation of chicken ESCs into PGCs, autophagy was activated and inhibited using rapamycin and bafilomycin A1, respectively. Results of qRT-PCR, flow cytometry, and indirect immunofluorescence showed that the efficiency of PGC formation significantly decreased after autophagy inhibition. Our results showed, for the first time, that autophagy plays an indispensable role in the formation of chicken PGCs, which lays the foundation for studying the mechanism of autophagy in chicken PGCs and in bird gene editing and the rescue of endangered birds.

Integrating RNA-seq and scRNA-seq to explore the mechanism of macrophage ferroptosis associated with COPD.

Aims: Our study focused on whether macrophages ferroptosis is associated with the pathogenesis of chronic obstructive pulmonary disease (COPD) or not. Main methods: We first identified macrophage module genes by weighted gene co-expression network analysis (WGCNA) in RNA sequencing (RNA-seq) date from COPD, and then identified macrophage marker genes by comprehensive analysis of single-cell RNA sequencing (scRNA-seq) data from COPD macrophages. There were 126 macrophage marker genes identified, and functional enrichment analyses indicated that ferroptosis pathway genes were significantly enriched. Secondly, we identified eight macrophage ferroptosis related genes and based on these eight genes, we performed co-expression analysis and drug prediction. Thirdly, two biomarkers (SOCS1 and HSPB1) were screened by the least absolute shrinkage and selection operator (LASSO), random forest (RF), and support vector machine-recursive feature elimination (SVM-RFE) and established an artificial neural network (ANN) for diagnosis. Subsequently, the biomarkers were validated in the dataset and validation set. These two biomarkers were then subjected to single gene-gene set enrichment analysis (GSEA) and gene set variation analysis (GSVA) analysis, and the ceRNA network was constructed. Finally, we carried out molecular validation with COPD models in vitro for cell counting kit-8 (CCK8) experiments, Western blot and quantitative real-time PCR (qRT-PCR) analysis and transmission electron microscopy (TEM). Key findings: This study revealed the vital role of macrophage ferroptosis in COPD, and novel biomarkers (SOCS1 and HSPB1) may be involved in the pathogenesis of COPD by regulating macrophage ferroptosis. Significance: Taken together, our results suggest that targeting SOCS1 and HSPB1 could treat COPD by inhibiting macrophage ferroptosis.

Mitochondrial haplotype modulates genome expression and mitochondrial structure/function in cardiomyocytes following volume overload.

Mitochondrial DNA (mtDNA) haplotype regulates mitochondrial structure/function and reactive oxygen species in aortocaval fistula (ACF) in mice. Here, we unravel the mitochondrial haplotype effects on cardiomyocyte mitochondrial ultrastructure and transcriptome response to ACF in vivo. Phenotypic responses and quantitative transmission electron microscopy (TEM) and RNA sequence at 3 days were determined after sham surgery or ACF in vivo in cardiomyocytes from wild-type (WT) C57BL/6J (C57n:C57mt) and C3H/HeN (C3Hn:C3Hmt) and mitochondrial nuclear exchange mice (C57n:C3Hmt or C3Hn:C57mt). Quantitative TEM of cardiomyocyte mitochondria C3HWT hearts have more electron-dense compact mitochondrial cristae compared with C57WT. In response to ACF, mitochondrial area and cristae integrity are normal in C3HWT; however, there is mitochondrial swelling, cristae lysis, and disorganization in both C57WT and MNX hearts. Tissue analysis shows that C3HWT hearts have increased autophagy, antioxidant, and glucose fatty acid oxidation-related genes compared with C57WT. Comparative transcriptomic analysis of cardiomyocytes from ACF was dependent upon mtDNA haplotype. C57mtDNA haplotype was associated with increased inflammatory/protein synthesis pathways and downregulation of bioenergetic pathways, whereas C3HmtDNA showed upregulation of autophagy genes. In conclusion, ACF in vivo shows a protective response of C3Hmt haplotype that is in large part driven by mitochondrial nuclear genome interaction.NEW & NOTEWORTHY The results of this study support the effects of mtDNA haplotype on nuclear gene expression in cardiomyocytes. Currently, there is no acceptable therapy for volume overload due to mitral regurgitation. The findings of this study could suggest that mtDNA haplotype activates different pathways after ACF warrants further investigations on human population of heart disease from different ancestry backgrounds.

Effect of small Sn addition on the initial strengthening and microstructural evolution of an Al-Cu-Mg-Ag alloy

The influence of small Sn addition on the mechanical properties and microstructure of an Al-Cu-Mg-Ag alloy is systematically investigated in this work. The age-hardening level of the material at 180 ℃, as well as the strength properties during exposing at 200 ℃, is found to decrease with small Sn addition. With Sn, the morphology of the tensile fracture surface gradually evolves from a transgranular mode to an intergranular one during the prolonged exposing at 200 ℃. Quantitative transmission electron microscopy (TEM) analysis proposes the negative role of Sn on the dense precipitation of Ω phase by accelerating the θ' formation, thereby leading to a loss of strength properties and the lower thermal stability of Sn-added alloy. This detrimental effect by Sn, as revealed by atom probe tomography (APT), is primarily ascribed to the suppressed Mg-Ag co-clustering, which reduces the nucleation rate of Ω phase. Our calculation also indicates that a reduction of the cluster hardening by Sn is mainly responsible for the observed loss in the strength of underaged alloy. The contributions of modulus hardening and order hardening to the cluster hardening are also quantified for each cluster. A similar recrystallized grain size in Sn-free and Sn-added alloys eliminates the grain refinement effect by Sn.

Paclitaxel, but Not Cisplatin, Affects Satellite Glial Cells in Dorsal Root Ganglia of Rats with Chemotherapy-Induced Peripheral Neurotoxicity

Chemotherapy-induced peripheral neurotoxicity is one of the most common dose-limiting toxicities of several widely used anticancer drugs such as platinum derivatives (cisplatin) and taxanes (paclitaxel). Several molecular mechanisms related to the onset of neurotoxicity have already been proposed, most of them having the sensory neurons of the dorsal root ganglia (DRG) and the peripheral nerve fibers as principal targets. In this study we explore chemotherapy-induced peripheral neurotoxicity beyond the neuronocentric view, investigating the changes induced by paclitaxel (PTX) and cisplatin (CDDP) on satellite glial cells (SGC) in the DRG and their crosstalk. Rats were chronically treated with PTX (10 mg/Kg, 1qwx4) or CDDP (2 mg/Kg 2qwx4) or respective vehicles. Morpho-functional analyses were performed to verify the features of drug-induced peripheral neurotoxicity. Qualitative and quantitative immunohistochemistry, 3D immunofluorescence, immunoblotting, and transmission electron microscopy analyses were also performed to detect alterations in SGCs and their interconnections. We demonstrated that PTX, but not CDDP, produces a strong activation of SGCs in the DRG, by altering their interconnections and their physical contact with sensory neurons. SGCs may act as principal actors in PTX-induced peripheral neurotoxicity, paving the way for the identification of new druggable targets for the treatment and prevention of chemotherapy-induced peripheral neurotoxicity.

Heat treatment-induced autophagy promotes breast cancer cell invasion and metastasis via TGF-β2-mediated epithelial-mesenchymal transitions.

Insufficient thermal ablation can accelerate malignant behaviors and metastases in some solid tumors, and epithelial-mesenchymal transition (EMT) and autophagy are involved in tumor metastasis. It has been found that TGF-β2 which belongs to the family of transforming growth factors often associated with cancer cell invasiveness and EMT. However, whether the interactions between autophagy and TGF-β2 induce EMT in breast cancer (BC) cells following insufficient microwave ablation (MWA) remains unclear. BC cells were treated with sublethal heat treatment to simulate insufficient MWA, and the effects of heat treatment on the BC cell phenotypes were explored. CCK-8, colony formation, flow cytometry, Transwell, and wound healing assays were performed to evaluate the influence of sublethal heat treatment on the proliferation, apoptosis, invasion, and migration of BC cells. Western blotting, real-time quantitative PCR, immunofluorescence, and transmission electron microscopy were carried out to determine the changes in markers associated with autophagy and EMT following sublethal heat treatment. Results showed that heat treatment promoted the proliferation of surviving BC cells, which was accompanied by autophagy induction. Heat treatment-induced autophagy up-regulated TGF-β2/Smad2 signaling and promoted EMT phenotype, thereby enhancing BC cells' migration and invasion abilities. An increase or decrease of TGF-β2 expression resulted in the potentiation and suppression of autophagy, as well as the enhancement and abatement of EMT. Autophagy inhibitors facilitated apoptosis and repressed proliferation of BC cells in vitro, and thwarted BC cell tumor growth and pulmonary metastasis in vivo. Heat treatment-induced autophagy promoted invasion and metastasis via TGF-β2/Smad2-mediated EMTs. Suppressing autophagy may be a suitable strategy for overcoming the progression and metastasis of residual BC cells following insufficient MWA.