Catalytic Nanoparticles in Biomedical Applications: Exploiting Advanced Nanozymes for Therapeutics and Diagnostics.

Catalytic nanoparticles (CNPs) as heterogeneous catalyst reveals superior activity due to their physio-chemical features, such as high surface-to-volume ratio and unique optical, electric, and magnetic properties. The CNPs, based on their physio-chemical nature, can either increase the reactive oxygen species (ROS) level for tumor and antibacterial therapy or eliminate the ROS for cytoprotection, anti-inflammation, and anti-aging. In addition, the catalytic activity of nanozymes could specifically trigger a specific reaction accompanied by the optical feature change, presenting the feasibility of biosensor and bioimaging applications. Undoubtedly, CNPs play a pivotal role in pushing the evolution of technologies in medical and clinical fields, and advanced strategies and nanomaterials rely on the input of chemical experts to develop. Herein, we present a systematic and comprehensive review of the challenges and recent development of catalytic NPs for biomedical applications from the viewpoint of advanced nanomaterial with unique catalytic activity and additional functions. Furthermore, we critically discuss the biosafety issue of applying biodegradable and non-biodegradable nanozymes and future perspectives to guide a promising direction in developing span-new nanozymes and more intelligent strategies for overcoming the current clinical limitations. This article is protected by copyright. All rights reserved.

Optogenetically engineered calcium oscillations promote autophagy-mediated cell death via AMPK activation.

Autophagy is a double-edged sword for cells; it can lead to both cell survival and death. Calcium (Ca2+) signalling plays a crucial role in regulating various cellular behaviours, including cell migration, proliferation and death. In this study, we investigated the effects of modulating cytosolic Ca2+ levels on autophagy using chemical and optogenetic methods. Our findings revealed that ionomycin and thapsigargin induce Ca2+ influx to promote autophagy, whereas the Ca2+ chelator BAPTA-AM induces Ca2+ depletion and inhibits autophagy. Furthermore, the optogenetic platform allows the manipulation of illumination parameters, including density, frequency, duty cycle and duration, to create different patterns of Ca2+ oscillations. We used the optogenetic tool Ca2+-translocating channelrhodopsin, which is activated and opened by 470 nm blue light to induce Ca2+ influx. These results demonstrated that high-frequency Ca2+ oscillations induce autophagy. In addition, autophagy induction may involve Ca2+-activated adenosine monophosphate (AMP)-activated protein kinases. In conclusion, high-frequency optogenetic Ca2+ oscillations led to cell death mediated by AMP-activated protein kinase-induced autophagy.

Diagnostic Value of Dual-Energy CT Virtual Noncalcium for the Assessment of Bone Marrow Edema of Wrist in Patients with Rheumatoid Arthritis.

RATIONALE AND OBJECTIVES: To evaluate the value of dual-energy CT (DECT) virtual noncalcium (VNCa) images in the diagnosis of wrist bone marrow edema (BME) in patients with rheumatoid arthritis (RA). MATERIALS AND METHODS: 43 patients with wrist involvement in active RA prospectively underwent DECT and MRI. Functional DECT images reconstruction yielded VNCa images. MRI served as the reference standard for diagnosing BME. BME diagnosis differences between VNCa images and MRI were compared. Differences in CT values between BME and normal bone marrow were assessed. The optimal CT value for detecting BME in VNCa images was determined through ROC curve analysis. The correlation between VNCa images scores and RA disease activity was evaluated. RESULTS: There was a high agreement between VNCa images and MRI in diagnosing BME (Kappa=0.831). VNCa images showed a significant difference in CT values between BME and normal bone marrow (P < 0.001). A cut-off value of - 54.8 HU yielded a sensitivity, specificity, and accuracy of 90.72%, 94.30%, and 93.33%, respectively, for detecting BME on VNCa images. The area under the ROC curve was 0.937 for distinguishing BME from normal bone marrow. Conventional CT images showed no statistically significant difference (P = 0.174) in CT values between BME and normal bone marrow. The VNCa images BME scores were positively correlated with RA disease activity (r = 0.399). CONCLUSION: The DECT VNCa technique demonstrates its potential for diagnosing wrist BME in patients with RA and provides a valuable tool for assessing disease activity in RA. IMPORTANT FINDINGS: The DECT VNCa technique has the ability to distinguish between BME and normal bone marrow. The VNCa images BME scores were positively correlated with the disease activity in RA.

Prussian blue analog with separated active sites to catalyze water driven enhanced catalytic treatments.

Chemodynamic therapy (CDT) uses the Fenton or Fenton-like reaction to yield toxic ‧OH following H2O2 → ‧OH for tumoral therapy. Unfortunately, H2O2 is often taken from the limited endogenous supply of H2O2 in cancer cells. A water oxidation CoFe Prussian blue (CFPB) nanoframes is presented to provide sustained, external energy-free self-supply of ‧OH from H2O to process CDT and/or photothermal therapy (PTT). Unexpectedly, the as-prepared CFPB nanocubes with no near-infrared (NIR) absorption is transformed into CFPB nanoframes with NIR absorption due to the increased Fe3+-N ≡ C-Fe2+ composition through the proposed proton-induced metal replacement reactions. Surprisingly, both the CFPB nanocubes and nanoframes provide for the self-supply of O2, H2O2, and ‧OH from H2O, with the nanoframe outperforming in the production of ‧OH. Simulation analysis indicates separated active sites in catalyzation of water oxidation, oxygen reduction, and Fenton-like reactions from CFPB. The liposome-covered CFPB nanoframes prepared for controllable water-driven CDT for male tumoral mice treatments.

Electroactive membrane fusion-liposome for increased electron transfer to enhance radiodynamic therapy.

Dynamic therapies have potential in cancer treatments but have limitations in efficiency and penetration depth. Here a membrane-integrated liposome (MIL) is created to coat titanium dioxide (TiO2) nanoparticles to enhance electron transfer and increase radical production under low-dose X-ray irradiation. The exoelectrogenic Shewanella oneidensis MR-1 microorganism presents an innate capability for extracellular electron transfer (EET). An EET-mimicking photocatalytic system is created by coating the TiO2 nanoparticles with the MIL, which significantly enhances superoxide anions generation under low-dose (1 Gy) X-ray activation. The c-type cytochromes-constructed electron channel in the membrane mimics electron transfer to surrounding oxygen. Moreover, the hole transport in the valence band is also observed for water oxidation to produce hydroxyl radicals. The TiO2@MIL system is demonstrated against orthotopic liver tumours in vivo.

Optogenetically engineered Ca2+ oscillation-mediated DRP1 activation promotes mitochondrial fission and cell death.

Mitochondrial dynamics regulate the quality and morphology of mitochondria. Calcium (Ca2+) plays an important role in regulating mitochondrial function. Here, we investigated the effects of optogenetically engineered Ca2+ signaling on mitochondrial dynamics. More specifically, customized illumination conditions could trigger unique Ca2+ oscillation waves to trigger specific signaling pathways. In this study, we found that modulating Ca2+ oscillations by increasing the light frequency, intensity and exposure time could drive mitochondria toward the fission state, mitochondrial dysfunction, autophagy and cell death. Moreover, illumination triggered phosphorylation at the Ser616 residue but not the Ser637 residue of the mitochondrial fission protein, dynamin-related protein 1 (DRP1, encoded by DNM1L), via the activation of Ca2+-dependent kinases CaMKII, ERK and CDK1. However, optogenetically engineered Ca2+ signaling did not activate calcineurin phosphatase to dephosphorylate DRP1 at Ser637. In addition, light illumination had no effect on the expression levels of the mitochondrial fusion proteins mitofusin 1 (MFN1) and 2 (MFN2). Overall, this study provides an effective and innovative approach to altering Ca2+ signaling for controlling mitochondrial fission with a more precise resolution than pharmacological approaches in the temporal dimension.

DNA tension assays reveal that force-dependent integrin activation regulates neurite outgrowth in primary cortical neurons.

Biomechanical inputs are ubiquitously present in biological systems and are known to regulate various cell functions. In particular, neural cell development is sensitive to mechanical regulation, as these cells reside in one of the softest microenvironments in the body. To fully characterize and comprehend how mechanical force modulates early neuronal processes, we prepared substrates functionalized with DNA probes displaying integrin ligands, including cRGD and laminin, to quantify integrin-mediated molecular tension during neurite initiation in primary cortical neurons. Our live-cell imaging analysis reveals that integrin-mediated tension force is highly dynamic and distributed across the cell body, with the overall tension signal gradually increasing during neurite outgrowth. Notably, we detected a consistent level of mechanical force (amplitude = 4.7-12 piconewtons, pN) for cell integrin-ligand interactions. Further quantifications reveal that neurons exhibit faster cell spreading and neurite outgrowth upon interacting with ligands functionalized with 4.7 pN relative to 12 pN probes. These findings indicate that the magnitude of integrin-mediated mechanical feedback regulates neuronal activity during early neuritogenesis. Additionally, we observed that mechanical tension is correlated with calcium signaling, since inhibiting calcium influx substantially reduced mechanical tension. Thus, our findings support that the magnitude of integrin-mediated mechanical feedback regulates neuronal activity during early neuritogenesis and that mechanical force is an essential element complementing well-known biochemical regulatory mechanisms orchestrating the integrin activation machinery and controlled neurite outgrowth in cortical neurons.

PREDICTING VISUAL OUTCOME AFTER SURGERY IN PATIENTS WITH IDIOPATHIC EPIRETINAL MEMBRANE USING A NOVEL CONVOLUTIONAL NEURAL NETWORK.

PURPOSE: To develop a deep convolutional neural network that enables the prediction of postoperative visual outcomes after epiretinal membrane surgery based on preoperative optical coherence tomography images and clinical parameters to refine surgical decision making. METHODS: A total of 529 patients with idiopathic epiretinal membrane who underwent standard vitrectomy with epiretinal membrane peeling surgery by two surgeons between January 1, 2014, and June 1, 2020, were enrolled. The newly developed Heterogeneous Data Fusion Net was introduced to predict postoperative visual acuity outcomes (improvement ≥2 lines in Snellen chart) 12 months after surgery based on preoperative cross-sectional optical coherence tomography images and clinical factors, including age, sex, and preoperative visual acuity. The predictive accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve of the convolutional neural network model were evaluated. RESULTS: The developed model demonstrated an overall accuracy for visual outcome prediction of 88.68% (95% CI, 79.0%-95.7%) with an area under the receiver operating characteristic curve of 97.8% (95% CI, 86.8%-98.0%), sensitivity of 87.0% (95% CI, 67.9%-95.5%), specificity of 92.9% (95% CI, 77.4%-98.0%), precision of 0.909, recall of 0.870, and F1 score of 0.889. The heatmaps identified the critical area for prediction as the ellipsoid zone of photoreceptors and the superficial retina, which was subjected to tangential traction of the proliferative membrane. CONCLUSION: The novel Heterogeneous Data Fusion Net demonstrated high accuracy in the automated prediction of visual outcomes after weighing and leveraging multiple clinical parameters, including optical coherence tomography images. This approach may be helpful in establishing personalized therapeutic strategies for epiretinal membrane management.

Hypoxia-induced YAP activation and focal adhesion turnover to promote cell migration in mesenchymal TNBC cells.

BACKGROUND: Hypoxia is commonly characterized by malignant tumors that promote the aggressiveness and metastatic potential of cancer. Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer, with approximately 46% capacity related to distant metastasis. Transcriptional factor yes-associated protein (YAP), a core component of the Hippo pathway, is associated with poor prognosis and outcome in cancer metastasis. Here, we explored the effect of hypoxia-mediated YAP activation and focal adhesions (FAs) turnover in mesenchymal TNBC cell migration. METHODS: We characterized the effect of hypoxia on YAP in different breast cancer cell lines using a hypoxia chamber and CoCl2 . RESULTS: Hypoxia-induced YAP nuclear translocation is significantly observed in normal breast epithelial cells, non-TNBC cells, mesenchymal TNBC cells, but not in basal-like TNBC cells. Functionally, we demonstrated that YAP activation was required for hypoxia to promote mesenchymal TNBC cell migration. Furthermore, hypoxia induced the localization of FAs at the leading edge of mesenchymal TNBC cells. In contrast, verteporfin (VP), a YAP inhibitor, significantly reduced the migration and the recruitment of nascent FAs at the cell periphery under hypoxia conditions, which only showed in mesenchymal TNBC cells. CONCLUSIONS: Our data support the hypothesis that YAP is novel factor and positively responsible for hypoxia-promoting mesenchymal TNBC cell migration. Our findings provide further evidence and outcomes to help prevent the progression of TNBC.

Engineering H2 O2 and O2 Self-Supplying Nanoreactor to Conduct Synergistic Chemiexcited Photodynamic and Calcium-Overloaded Therapy in Orthotopic Hepatic Tumors.

Photodynamic therapy (PDT) is traditionally ineffective for deeply embedded tumors due to the poor penetration depth of the excitation light. Chemiluminescence resonance energy transfer (CRET) has emerged as a promising mode of PDT without external light. To date, related research has frequently used endogenous hydrogen peroxide (H2 O2 ) and oxygen (O2 ) inside the solid tumor microenvironment to trigger CRET-mediated PDT. Unfortunately, this significantly restricts treatment efficacy and the development of further biomedical applications because of the limited amounts of endogenous H2 O2 and O2 . Herein, a nanohybrid (mSiO2 /CaO2 /CPPO/Ce6: mSCCC) nanoparticle (NP) is designed to achieve synergistic CRET-mediated PDT and calcium (Ca2+ )-overload-mediated therapy. The calcium peroxide (CaO2 ) formed inside mesoporous SiO2 (mSC) with the inclusion of the chemiluminescent agent (CPPO) and photosensitizer (Ce6) self-supplies H2 O2 , O2 , and Ca2+ allowing for the subsequent treatments. The Ce6 in mSCCC NPs is excited by chemical energy in situ following the supply of H2 O2 and O2 to produce singlet oxygen (1 O2 ). The nanohybrid NPs are coated with stearic acid to avoid decomposition during blood circulation through contact with aqueous environment. This nanohybrid shows promising performance in the generation of 1 O2 for external light-free PDT and the release of Ca2+ ions for Ca2+ -overloaded therapy against orthotopic hepatocellular carcinoma.

Widen the Applicability of a Convolutional Neural-Network-Assisted Glaucoma Detection Algorithm of Limited Training Images across Different Datasets.

Automated glaucoma detection using deep learning may increase the diagnostic rate of glaucoma to prevent blindness, but generalizable models are currently unavailable despite the use of huge training datasets. This study aims to evaluate the performance of a convolutional neural network (CNN) classifier trained with a limited number of high-quality fundus images in detecting glaucoma and methods to improve its performance across different datasets. A CNN classifier was constructed using EfficientNet B3 and 944 images collected from one medical center (core model) and externally validated using three datasets. The performance of the core model was compared with (1) the integrated model constructed by using all training images from the four datasets and (2) the dataset-specific model built by fine-tuning the core model with training images from the external datasets. The diagnostic accuracy of the core model was 95.62% but dropped to ranges of 52.5-80.0% on the external datasets. Dataset-specific models exhibited superior diagnostic performance on the external datasets compared to other models, with a diagnostic accuracy of 87.50-92.5%. The findings suggest that dataset-specific tuning of the core CNN classifier effectively improves its applicability across different datasets when increasing training images fails to achieve generalization.

Chemoresistant ovarian cancer enhances its migration abilities by increasing store-operated Ca2+ entry-mediated turnover of focal adhesions.

BACKGROUND: Among gynecological cancers, ovarian carcinoma has the highest mortality rate, and chemoresistance is highly prevalent in this cancer. Therefore, novel strategies are required to improve its poor prognosis. Formation and disassembly of focal adhesions are regulated dynamically during cell migration, which plays an essential role in cancer metastasis. Metastasis is intricately linked with resistance to chemotherapy, but the molecular basis for this link is unknown. METHODS: Transwell migration and wound healing migration assays were used to analyze the migration ability of ovarian cancer cells. Real-time recordings by total internal reflection fluorescence microscope (TIRFM) were performed to assess the turnover of focal adhesions with fluorescence protein-tagged focal adhesion molecules. SOCE inhibitors were used to verify the effects of SOCE on focal adhesion dynamics, cell migration, and chemoresistance in chemoresistant cells. RESULTS: We found that mesenchymal-like chemoresistant IGROV1 ovarian cancer cells have higher migration properties because of their rapid regulation of focal adhesion dynamics through FAK, paxillin, vinculin, and talin. Focal adhesions in chemoresistant cells, they were smaller and exhibited strong adhesive force, which caused the cells to migrate rapidly. Store-operated Ca2+ entry (SOCE) regulates focal adhesion turnover, and cell polarization and migration. Herein, we compared SOCE upregulation in chemoresistant ovarian cancer cells to its parental cells. SOCE inhibitors attenuated the assembly and disassembly of focal adhesions significantly. Results of wound healing and transwell assays revealed that SOCE inhibitors decreased chemoresistant cell migration. Additionally, SOCE inhibitors combined with chemotherapeutic drugs could reverse ovarian cancer drug resistance. CONCLUSION: Our findings describe the role of SOCE in chemoresistance-mediated focal adhesion turnover, cell migration, and viability. Consequently, SOCE might be a promising therapeutic target in epithelial ovarian cancer.

Simple In-House Fabrication of Microwells for Generating Uniform Hepatic Multicellular Cancer Aggregates and Discovering Novel Therapeutics.

Three-dimensional (3D) cell culture models have become powerful tools because they better simulate the in vivo pathophysiological microenvironment than traditional two-dimensional (2D) monolayer cultures. Tumor cells cultured in a 3D system as multicellular cancer aggregates (MCAs) recapitulate several critical in vivo characteristics that enable the study of biological functions and drug discovery. The microwell, in particular, has emerged as a revolutionary technology in the generation of MCAs as it provides geometrically defined microstructures for culturing size-controlled MCAs amenable for various downstream functional assays. This paper presents a simple and economical microwell fabrication methodology that can be conveniently incorporated into a conventional laboratory setting and used for the discovery of therapeutic interventions for liver cancer. The microwells were 400-700 µm in diameter, and hepatic MCAs (Huh-7 cells) were cultured in them for up to 5 days, over which time they grew to 250-520 µm with good viability and shape. The integrability of the microwell fabrication with a high-throughput workflow was demonstrated using a standard 96-well plate for proof-of-concept drug screening. The IC50 of doxorubicin was determined to be 9.3 µM under 2D conditions and 42.8 µM under 3D conditions. The application of photothermal treatment was demonstrated by optimizing concanavalin A-FITC conjugated silica-carbon hollow spheres (SCHSs) at a concentration of 500:200 µg/mL after a 2 h incubation to best bind with MCAs. Based on this concentration, which was appropriate for further photothermal treatment, the relative cell viability was assessed through exposure to a 3 W/cm2 near-infrared laser for 20 min. The relative fluorescence intensity showed an eight-fold reduction in cell viability, confirming the feasibility of using photothermal treatment as a potential therapeutic intervention. The proposed microwell integration is envisioned to serve as a simple in-house technique for the generation of MCAs useful for discovering therapeutic modalities for liver cancer treatment.

Cystic Fibrosis Transmembrane Conductance Regulator: A Possible New Target for Photodynamic Therapy Enhances Wound Healing.

Objective: Cell migration is an essential process in skin wound healing. Photodynamic therapy (PDT) enhances wound healing by photoactivating a photosensitizer with a specific wavelength of light. Cystic fibrosis transmembrane conductance regulator (CFTR) is an ion channel expressed in multiple layers of keratinocytes. Recent studies showed that the activation of CFTR-related downstream signaling affects skin wound healing. We examined whether indocyanine green (ICG)-mediated PDT-enhanced cell migration is related to CFTR activation. Approach: The spatial and temporal expression levels of CFTR and proteins involved in focal adhesion, including focal adhesion kinase (FAK) and paxillin, were evaluated during cell migration in vitro and in vivo for wound healing. Results: ICG-PDT-conditioned medium collected from cells exposed to 5 J/cm2 near-infrared light in the presence of 100 µg/mL ICG activated CFTR and enhanced HaCaT cell migration. The expression of phosphorylated FAK Tyr861 and phosphorylated paxillin in focal adhesions was spatially and temporally regulated in parallel by ICG-PDT-conditioned medium. Curcumin, a nonspecific activator of CFTR, further increased PDT-enhanced cell migration, whereas inhibition of CFTR and FAK delayed cell migration. The involvement of CFTR in ICG-PDT-enhanced skin wound healing was confirmed in a mouse back skin wound model. Innovation: CFTR is a potential new therapeutic target in ICG-PDT to enhance wound healing. Conclusion: ICG-PDT-enhanced cell migration may be related to activation of the CFTR and FAK pathway. Conditioned medium collected from ICG-PDT may be useful for treating patients with chronic skin ulcer by regulating CFTR expression in keratinocytes.

Galectin-12 is Involved in Corn Silk-Induced Anti-Adipogenesis and Anti-Obesity Effects.

Obesity is a significant risk factor for various diseases. It is a clinical condition caused by the excessive accumulation of fat, which has a negative impact on human health. Galactin-12 is an adipocyte-expressed protein and possesses adipocyte-inducing activity. We investigated the expression level of candidate proteins involved in galactin-12-mediated adipocyte differentiation pathway. We performed a high-throughput screening assay to monitor galectin-12 promoter activity using 105 traditional Chinese herbs. Corn silk extract and [Formula: see text]-sitosterol reduced the expression of galactin-12 promoter in 3T3-L1 cells. In addition, corn silk extract and [Formula: see text]-sitosterol decreased the level of lipid droplets and downregulated the gene and protein expression level of C/EBP[Formula: see text], C/EBP[Formula: see text], PPAR[Formula: see text], Ap2, and adipsin in 3T3-L1 pre-adipocytes via AKT and ERK1/2 inhibition. In vivo study with the oral administration of corn silk extract and [Formula: see text]-sitosterol in a mouse model showed a significant weight reduction and decrease in adipocytes in several organs such as the liver and adipose tissue. Taken together, corn silk extract and [Formula: see text]-sitosterol may effectively reduce pre-adipocyte differentiation by inhibiting galectin-12 activity and exerting anti-obesity effects. These findings highlight the potential use of corn silk extract and [Formula: see text]-sitosterol as potential candidates for the prevention and treatment of obesity.

STIM1 Knockout Enhances PDGF-Mediated Ca2+ Signaling through Upregulation of the PDGFR⁻PLCγ⁻STIM2 Cascade.

Platelet-derived growth factor (PDGF) has mitogenic and chemotactic effects on fibroblasts. An increase in intracellular Ca2+ is one of the first events that occurs following the stimulation of PDGF receptors (PDGFRs). PDGF activates Ca2+ elevation by activating the phospholipase C gamma (PLCγ)-signaling pathway, resulting in ER Ca2+ release. Store-operated Ca2+ entry (SOCE) is the major form of extracellular Ca2+ influx following depletion of ER Ca2+ stores and stromal interaction molecule 1 (STIM1) is a key molecule in the regulation of SOCE. In this study, wild-type and STIM1 knockout mouse embryonic fibroblasts (MEF) cells were used to investigate the role of STIM1 in PDGF-induced Ca2+ oscillation and its functions in MEF cells. The unexpected findings suggest that STIM1 knockout enhances PDGFR⁻PLCγ­STIM2 signaling, which in turn increases PDGF-BB-induced Ca2+ elevation. Enhanced expressions of PDGFRs and PLCγ in STIM1 knockout cells induce Ca2+ release from the ER store through PLCγ­IP3 signaling. Moreover, STIM2 replaces STIM1 to act as the major ER Ca2+ sensor in activating SOCE. However, activation of PDGFRs also activate Akt, ERK, and JNK to regulate cellular functions, such as cell migration. These results suggest that alternative switchable pathways can be observed in cells, which act downstream of the growth factors that regulate Ca2+ signaling.

Allyl Isothiocyanate Ameliorates Obesity by Inhibiting Galectin-12.

SCOPE: The aim of this study is to investigate the signaling pathways by which allyl isothiocyanate (AITC) reduces adipocyte differentiation and the efficacy of AITC in suppressing galectin-12 levels as a therapeutic for high fat diet (HFD)-induced obesity. METHODS AND RESULTS: AITC presents anti-adipogenic effects on 3T3-L1 cells by decreasing lipid droplet accumulation in a dose-dependent manner. AITC suppresses 3T3-L1 differentiation into adipocytes by decreasing galectin-12 expression and by downregulating key adipogenic transcription factors. AITC influences the expression of 3T3-L1 pre-adipocytes by modulating adipokine expression (leptin and resistin) and by regulating the protein kinase B (PKB/Akt)/cAMP response element-binding protein (CREB) pathway. In HFD-fed mice, oral administration of AITC reduces the body weight, accumulation of lipid droplets in the liver, and white adipocyte size. CONCLUSION: In summary, the results indicate that AITC inhibits adipocyte differentiation by suppressing galectin-12 levels in 3T3L1 cells and has antiobesity effects in HFD-fed mice.

Chemo-photothermal effects of doxorubicin/silica-carbon hollow spheres on liver cancer.

Chemo-photothermal therapy, which exhibits synergistic effects, is more effective than either of the treatments administered alone because of its superior ability to target and destroy cancer cells. An anti-cancer compound (doxorubicin, DOX) was embedded in silica-carbon hollow spheres (SCHSs) using heat and vacuum to integrate multi-therapeutic effects onto one platform and subsequently improve the anti-cancer efficacy. SCHSs were synthesized via a surface activation method and its highly porous surface enhanced the loading content of the desired drug. SCHSs are an infrared photothermal material that can destroy targeted cells by heating under near-infrared (NIR) laser illumination at 808 nm. NIR laser illumination also enhances DOX release from SCHSs to increase the anti-cancer efficiency of DOX-loaded SCHSs (DOX-SCHSs) in both two-dimensional and three-dimensional multicellular tumor spheroid cultures. SCHSs exhibited high heat-generating ability and pH-responsive drug delivery. In conclusion, this study demonstrated that DOX-SCHSs represent a potential tool for chemo-photothermal therapy due to its photothermal effects. Thus, our findings imply that the high cancer cell killing efficiency of DOX-SCHSs induced by NIR illumination can be used for the treatment of tumors.

Differential Ca2+ mobilization and mast cell degranulation by FcεRI- and GPCR-mediated signaling.

Mast cells play a primary role in allergic diseases. During an allergic reaction, mast cell activation is initiated by cross-linking IgE-FcεRI complex by multivalent antigen resulting in degranulation. Additionally, G protein-coupled receptors also induce degranulation upon activation. However, the spatio-temporal relationship between Ca2+ mobilization and mast cell degranulation is not well understood. We investigated the relationship between oscillations in Ca2+ level and mast cell degranulation upon stimulation in rat RBL-2H3 cells. Nile red and Fluo-4 were used as probes for monitoring histamine and intracellular Ca2+ levels, respectively. Histamine release and Ca2+ oscillations in real-time were monitored using total internal reflection fluorescence microscopy (TIRFM). Mast cell degranulation followed immediately after FcεRI and GPCR-mediated Ca2+ increase. FcεRI-induced Ca2+ increase was higher and more sustained than that induced by GPCRs. However, no significant difference in mast cell degranulation rates was observed. Although intracellular Ca2+ release was both necessary and sufficient for mast cell degranulation, extracellular Ca2+ influx enhanced the process. Furthermore, cytosolic Ca2+ levels and mast cell degranulation were significantly decreased by downregulation of store-operated Ca2+ entry (SOCE) via Orai1 knockdown, 2-aminoethyl diphenylborinate (2-APB) or tubastatin A (TSA) treatment. Collectively, this study has demonstrated the role of Ca2+ signaling in regulating histamine degranulation.

Revealing the three dimensional architecture of focal adhesion components to explain Ca2+-mediated turnover of focal adhesions.

BACKGROUND: Focal adhesions (FAs) are large, dynamic protein complexes located close to the plasma membrane, which serve as the mechanical linkages and a biochemical signaling hub of cells. The coordinated and dynamic regulation of focal adhesion is required for cell migration. Degradation, or turnover, of FAs is a major event at the trailing edge of a migratory cell, and is mediated by Ca2+/calpain-dependent proteolysis and disassembly. Here, we investigated how Ca2+ influx induces cascades of FA turnover in living cells. METHODS: Images obtained with a total internal reflection fluorescence microscope (TIRFM) showed that Ca2+ ions induce different processes in the FA molecules focal adhesion kinase (FAK), paxillin, vinculin, and talin. Three mutated calpain-resistant FA molecules, FAK-V744G, paxillin-S95G, and talin-L432G, were used to clarify the role of each FA molecule in FA turnover. RESULTS: Vinculin was resistant to degradation and was not significantly affected by the presence of mutated calpain-resistant FA molecules. In contrast, talin was more sensitive to calpain-mediated turnover than the other molecules. Three-dimensional (3D) fluorescence imaging and immunoblotting demonstrated that outer FA molecules were more sensitive to calpain-mediated proteolysis than internal FA molecules. Furthermore, cell contraction is not involved in degradation of FA. CONCLUSIONS: These results suggest that Ca2+-mediated degradation of FAs was mediated by both proteolysis and disassembly. The 3D architecture of FAs is related to the different dynamics of FA molecule degradation during Ca2+-mediated FA turnover. GENERAL SIGNIFICANCE: This study will help us to clearly understand the underlying mechanism of focal adhesion turnover by Ca2+.