A Photopolymerized Semi-Interpenetrating Polymer Networks-Based Hydrogel Incorporated with Nanoparticle for Local Chemotherapy of Tumors.

PURPOSE: To address the issue of local drug delivery in tumor treatment, a novel nanoparticle-hydrogel superstructure, namely semi-interpenetrating polymer networks (semi-IPNs) hydrogel composed of poly (ethylene glycol) diacrylate (PEGDA) and hyaluronic acid (HA) and incorporated with paclitaxel (PTX) loaded PLGA nanoparticles (PEGDA-HA/PLGA-PTX), was prepared by in situ UV photopolymerization for the use of local drug delivery. METHODS: Using the gelation time, swelling rate and degradation rate as indicators, the optimal proportion of Irgacure 2959 initiator and the concentration of HA was screened and obtained for preparing hydrogels. Next, paclitaxel (PTX) loaded PLGA nanoparticles (PLGA-PTX NPs) were prepared by the emulsion solvent evaporation method. RESULTS: The mass ratio of the initiator was 1%, and the best concentration of HA was 5 mg/mL in PEGDA-HA hydrogel. In vitro experiments showed that PLGA-PTX NPs had similar cytotoxicity to free PTX, and the cell uptake ratio on NCI-H460 cells was up to 96% by laser confocal microscopy and flow cytometry. The drug release of the PEGDA-HA/PLGA-PTX hydrogel local drug delivery system could last for 13 days. In vivo experiments proved that PEGDAHA/PLGA-PTX hydrogel could effectively inhibit the tumor growth without causing toxic effects in mice. CONCLUSIONS: This study demonstrated that the PEGDA-HA/PLGA-PTX hydrogel is a promising local drug delivery system in future clinical applications for tumor therapy. A photopolymerized semi-interpenetrating polymer networks-based hydrogel incorporated with paclitaxel-loaded nanoparticles was fabricated by in situ UV photopolymerization, providing a promised nanoplatform for local chemotherapy of tumors.

Chemically modified liposomes carrying TRAIL target activated hepatic stellate cells and ameliorate hepatic fibrosis in vitro and in vivo.

At present, no satisfactory anti-liver fibrosis drugs have been used clinically due to the poor targeting ability and short half-life period. This study aimed to explore the effects of a new TRAIL (TNF-related apoptosis-inducing ligand) preparation that can target aHSCs (activated hepatic stellate cells) on liver fibrosis and explain the possible underlying mechanism. Using our self-made drug carrier pPB-SSL that specifically targets aHSCs, recombinant human TRAIL (rhTRAIL) protein was embedded in (named as pPB-SSL-TRAIL) and applied to treat liver fibrotic mice as well as 3T3 fibroblast cells and aHSCs. Through in vitro and in vivo experiments, we found that, compared with the groups treated with TRAIL (free rhTRAIL) and SSL-TRAIL (rhTRAIL capsulated within unmodified liposome), the group treated with pPB-SSL-TRAIL nanoparticles showed significantly lower cell viability and higher cell apoptosis in vitro. The targeting delivering system pPB-SSL also significantly enhanced the anti-fibrotic effect, apoptosis induction and long circulation of rhTRAIL. After the treatment with pPB-SSL-TRAIL, apoptosis of aHSCs was notably increased and hepatic fibrosis in mice was remarkably alleviated. In vitro, pPB-SSL-TRAIL nanoparticles were mainly transported and located on membrane or into cytoplasm, but the particles were distributed mainly in mouse fibrotic liver and most on the cell membrane of aHSCs. In conclusion, rhTRAIL carried by pPB-SSL delivering system has prolonged circulation in blood, be able to target aHSCs specifically, and alleviate fibrosis both in vitro and in vivo. It presents promising prospect in the therapy of liver fibrosis, and it is worthwhile for us to develop it for clinical use.

Erythrocyte Membrane-Wrapped pH Sensitive Polymeric Nanoparticles for Non-Small Cell Lung Cancer Therapy.

The application of nano drug delivery systems (NDDSs) may enhance the effectiveness of chemotherapeutic drugs in vivo. However, the short blood circulation time and poor drug release profile in vivo are still two problems with them. Herein, by using red blood cell membrane (RBCm) wrapping and pH sensitive technology, we prepared RBCm wrapped pH sensitive poly(l-γ-glutamylcarbocistein)-paclitaxel (PGSC-PTX) nanoparticles (PGSC-PTX@RBCm NPs), to prolong the circulation time in blood and release PTX timely and adequately in acidic tumor environment. The PGSC-PTX NPs and PGSC-PTX@RBCm NPs showed spherical morphology with average sizes about 50 and 100 nm, respectively. The cytotoxicity of PGSC-PTX@RBCm NPs was considerably decreased compared with that of PGSC-PTX NPs. PTX release from PGSC-PTX and PGSC-PTX@RBCm NPs at pH 6.5 was remarkably higher than those at pH 7.4, respectively. The PGSC-PTX@RBCm NPs exhibited remarkably decreased uptake by macrophages than PGSC-PTX NPs. The area under the curve within 72 h (AUC0-72h) for is significantly higher than PGSC-PTX NPs. The PGSC-PTX@RBCm NPs also showed significantly stronger growth-inhibiting effect on tumor than PGSC-PTX NPs. These results indicated that PGSC-PTX@RBCm NPs have acidic drug release sensitivity, the characteristics of long circulation, and remarkable tumor growth inhibiting effect. This study may provide an effective strategy for improving the antitumor effect of NDDS.

iNGR-Modified Liposomes for Tumor Vascular Targeting and Tumor Tissue Penetrating Delivery in the Treatment of Glioblastoma.

The tumor vascular barrier and tumor stroma barrier become the two main obstacles in the in vivo delivery of nanomedicines. In this study, to overcome the two barriers, we used iNGR, a tumor-penetrating peptide, to modify the liposomes to increase their accumulation and penetration in tumor tissues. First, iNGR-modified sterically stabilized liposomes (iNGR-SSL) were prepared, which showed vesicle sizes of about 100 nm and narrow size distribution. The uptake of iNGR-SSL by U87MG cells and HUVECs were significantly more than that of unmodified liposome. The in vivo imaging study demonstrated that iNGR modification remarkably increased the accumulation of the liposome in orthotopic tumor tissues of animal model. The immunofluorescence staining analysis proved that iNGR-SSL could penetrate through tumor blood vessels and into the deep tumor tissues. The cytotoxicity of iNGR-modified doxorubicin-loaded liposomes (iNGR-SSL/DOX) on U87MG and HUVECs cells in vitro was significantly enhanced than that of unmodified doxorubicin-loaded liposomes (SSL/DOX). The iNGR-SSL/DOX also showed comparatively (p < 0.05) stronger cytotoxicity on tumor than SSL/DOX, which should be resulted from the increased tumor accumulation and penetration mediated by iNGR. This study proved that iNGR peptide modification might be an effective method to enhance the tumor penetrating ability of liposomes in tumor tissue and their antitumor effect.

Poly (l-γ-glutamylglutamine) Polymer Enhances Doxorubicin Accumulation in Multidrug Resistant Breast Cancer Cells.

BACKGROUND: Drug resistance is one of the bottlenecks of cancer chemotherapy in the clinic. Polymeric nanomedicine is one of the most promising strategies for overcoming poor chemotherapy responses due to the multidrug resistance (MDR). METHODS: In this study, a new polymer-based drug delivery system, poly (l-γ-glutamylglutamine)-doxorubicin (PGG-Dox) conjugate, was studied in both drug-induced resistant human breast cancer MDA-MB-231/MDR cells and their parent human breast cancer MDA-MB-231 cells. The effect of PGG on facilitating the growth inhibition of Dox against multidrug resistant cells were investigated by evaluating the cytotoxicity of PGG-Dox conjugate, PGG/Dox unconjugated complex and free Dox on both cells. The underlying mechanisms in resistant cells were further studied via the intracellular traffic studies. RESULTS: Both conjugated and unconjugated PGG significantly increased Dox uptake, prolonged Dox retention and reduced Dox efflux in the MDA-MB-231/MDR cells. The PGG-Dox conjugate is taken up by tumor cells mainly by pinocytosis pathway, in which PGG-Dox conjugate-containing vesicles are formed and enter the cells. CONCLUSIONS: This study indicated that both polymer-drug conjugate and unconjugated complex are promising strategies of overcoming resistance of anti-tumor drugs.

Retro-inverso CendR peptide-mediated polyethyleneimine for intracranial glioblastoma-targeting gene therapy.

The development of nonviral gene delivery vectors offers the potential to provide effective treatment for glioblastoma in the form of gene therapy. Here, we report the use of retro-inverso C-end rule (CendR) peptide D(RPPREGR) as a targeting ligand to prepare a D(RPPREGR)-PEG-PEI gene vector. D(RPPREGR) peptide specifically recognized the neuropilin-1 receptor that was overexpressed on U87 glioma cells, and showed enhanced tumor spheroid penetration ability. Compared with parental RGERPPR, D(RPPREGR) possessed improved biological stability and had a higher affinity for U87 glioma cells; it also showed enhanced penetration of the tumor spheroid. mPEG-PEI/pDNA and D(RPPREGR)-PEG-PEI/pDNA complexes were prepared and MTT assay results revealed that the cytotoxicity of D(RPPREGR)-PEG-PEI complexes was significantly lower than that of PEI complexes, with cell survival rates above 80%. Qualitative and quantitative in vitro transfection results revealed that D(RPPREGR)-PEG-PEI complex transfection efficiencies were 1.9 times higher than those of mPEG-PEI. Fluorescent imaging and frozen sections of brain tissue demonstrated that the D(RPPREGR) modification improved the in vivo transfection efficiency of mPEG-PEI in nude mice bearing U87 gliomas. An antiglioblastoma assay revealed that D(RPPREGR)-PEG-PEI carrying the therapeutic gene pORF-hTRAIL significantly prolonged the survival time of intracranial U87 glioma-bearing mice from 25 to 30 days. Therefore, D(RPPREGR)-PEG-PEI appears to be suitable for use as a safe and efficient gene delivery vehicle with potential applications in glioblastoma gene therapy.

Tumor-penetrating peptide mediation: an effective strategy for improving the transport of liposomes in tumor tissue.

Currently, the inefficient transport of liposomes in tumor tissue hinders their clinical application. Tumor-penetrating peptides (TPP) are a series of targeting peptides with the function of penetrating tumor blood vessels and tumor stroma. This work aimed to improve the penetration of liposomes in tumor tissues by TPP modification, thereby enhancing the antitumor effect. First, RPARPAR, a TPP, was modified to the surface of liposomes loaded with doxorubicin. The RPARPAR-modified liposomes (RPA-LP) and unmodified liposomes (LP) showed spherical morphology with average sizes about 90 nm. RPA-LP exhibited remarkably increased cellular accumulation by PC-3 tumor cells than LP as evidenced by the cellular uptake test. The in vivo imaging study confirmed that RPARPAR modification significantly increased the liposome accumulation in subcutaneous tumor tissues. RPA-LP could penetrate through tumor blood vessels and tumor stroma and into the deep tumor tissues as evidence by the immunofluorescence staining analysis. The cytotoxicity of RPARPAR-modified doxorubicin liposomes (RPA-LP-DXR) is considerably increased compared with that of doxorubicin liposomes (LP-DXR). The RPA-LP-DXR also showed significantly (p < 0.005) stronger growth-inhibiting effect on tumor than LP-DXR, possibly due to the tumor-penetrating ability of RPA-LP and targeted killing of tumor cells. This study proved that TPP mediation may be an effective strategy for improving the transport of liposomes in tumor tissue.

Tumor-penetrating peptide functionalization enhances the anti-glioblastoma effect of doxorubicin liposomes.

The targeted therapeutic effect of nano drug delivery system for glioblastoma has been hampered by the weak enhanced permeability and retention (EPR) effect of glioblastoma and the low delivering efficiency of NDDS in glioblastoma tissue. In this study, a tumor-penetrating peptide (RGERPPR), the specific ligand of neuropilin-1 overexpressed on glioblastoma and endothelial cells, was used as a targeting moiety to enhance the anti-glioblastoma effect of doxorubicin liposomes. Firstly, RGERPPR-PEG-DSPE was synthesized and used to prepare the RGERPPR peptide-functionalized liposomes (RGE-LS), which showed vesicle sizes of around 90 nm and narrow size distributions. The cellular uptake and in vivo near-infrared fluorescence imaging test displayed that RGE-LS exhibited increased uptake by glioblastoma cells and intracranial glioblastoma tissues. The cytotoxicity assay and anti-glioblastoma study proved that RGERPPR functionalization significantly enhanced the in vitro inhibitory effect of doxorubicin liposomes on glioblastoma cells and prolonged the median survival time of nude mice bearing intracranial glioblastoma. Finally, the immunofluorescence analysis evidenced that RGE-LS were able to penetrate through tumor vessels and stroma and deep into the whole tumor tissue. The results indicated that tumor-penetrating peptide functionalization is an effective strategy for enhancing the anti-glioblastoma effect of doxorubicin liposomes.

The improving effects on hepatic fibrosis of interferon-γ liposomes targeted to hepatic stellate cells.

No satisfactory anti-fibrotic therapies have yet been applied clinically. One of the main reasons is the inability to specifically target the responsible cells to produce an available drug concentration and the side-effects. Exploiting the key role of the activated hepatic stellate cells (HSCs) in both hepatic fibrogenesis and over-expression of platelet-derived growth factor receptor- (PDGFR- ), we constructed targeted sterically stable liposomes (SSLs) modified by a cyclic peptide (pPB) with affinity for the PDGFR- to deliver interferon (IFN)- to HSCs. The pPB-SSL-IFN- showed satisfactory size distribution. In vitro pPB-SSL could be taken up by activated HSCs. The study of tissue distribution via living-body animal imaging showed that the pPB-SSL-IFN- mostly accumulated in the liver until 24 h. Furthermore, the pPB-SSL-IFN- showed more significant remission of hepatic fibrosis. In vivo the histological Ishak stage, the semiquantitative score for collagen in fibrotic liver and the serum levels of collagen type IV-C in fibrotic rats treated with pPB-SSL-IFN- were less than those treated with SSL-IFN- , IFN- and the control group. In vitro pPB-SSL-IFN- was also more effective in suppressing activated HSC proliferation and inducing apoptosis of activated HSCs. Thus the data suggest that pPB-SSL-IFN- might be a more effective anti-fibrotic agent and a new opportunity for clinical therapy of hepatic fibrosis.

Hepatic macrophage targeted siRNA lipid nanoparticles treat non-alcoholic steatohepatitis.

HMGB1 is an inflammatory factor produced by macrophages after liver injury, which plays a key role in promoting NASH progression and further developing into liver fibrosis and cirrhosis. In this study, a mannose-modified HMGB1-siRNA loaded stable nucleic acid lipid particle delivery system (mLNP-siHMGB1) was constructed to target liver macrophages with mannose receptor mediation, thereby silencing HMGB1 protein expression and treating NASH. We also examined the effect of co-administration with docosahexaenoic acid (DHA), a kind of unsaturated fatty acid, on NASH. The results showed that mLNP-siHMGB1 could target macrophages through mannose receptors, effectively silence HMGB1 gene, reduce the release of HMGB1 protein in the liver, regulate liver macrophages to be an anti-inflammatory M2 phenotype, effectively reduce hepatic lobular inflammation and bullous steatosis in the liver, and restore the liver function of NASH model mice to a normal level. After 8 weeks of combined treatment with mLNP-siHMGB1 and DHA, the liver function of NASH model mice recovered rapidly and the hepatic steatosis returned to normal level. In view of inflammation, a key factor in the progression of NASH, we provided an actively targeted siRNA delivery system in this study, and clarified the important role of the delivery system in phenotypic regulation of liver macrophages in NASH. In addition, we also demonstrated the effectiveness of DHA co-administration in NASH treatment. This study provided a useful idea and scientific basis for the development of therapeutic strategies for NASH in the future.

Lipid nanoparticles produce chimeric antigen receptor T cells with interleukin-6 knockdown in vivo.

Chimeric receptor T cells (CAR-T) can effectively cure leukemia; however, there are two limitations: a complicated preparation process ex vivo and cytokine release syndrome (CRS). In this study, we constructed a lipid nanoparticle system modified by CD3 antibody on the surface, loading with the plasmid containing the combination gene of interleukin 6 short hairpin RNA (IL-6 shRNA) and CD19-CAR (AntiCD3-LNP/CAR19 + shIL6). The system targeted T cells by the mediation of CD3 antibody and stably transfected T cells to transform them into CAR-T cells with IL-6 knockdown, thus killing CD19-highly expressed leukemia tumor cells and reducing CRS caused by IL-6. In vivo experiments showed that AntiCD3-LNP/CAR19 + shIL6 could stably transfect T cells and produce CAR-T within 90 days to kill the tumor. This significantly prolonged the survival time of leukemia model mice and demonstrated the prepared LNP exhibited the same anti-tumor effect as the traditional CAR-T cells prepared ex vivo. In this study, CAR-T cells were directly produced in vivo after intravenous injection of the lipid nanoparticles, without the need of using the current complex process ex vivo. Additionally, IL-6 expression was silenced, which would be helpful to reduce the CRS and improve the safety of CAR-T therapy. This method improves the convenience of using CAR-T technology and is helpful in further promoting the clinical application of CAR-T.

Nanoengineered Neutrophils as a Cellular Sonosensitizer for Visual Sonodynamic Therapy of Malignant Tumors.

The rapid evolution of cell-based theranostics has attracted extensive attention due to their unique advantages in biomedical applications. However, the inherent functions of cells alone cannot meet the needs of malignant tumor treatment. Thus endowing original cells with new characteristics to generate multifunctional living cells may hold a tremendous promise. Here, the nanoengineering method is used to combine customized liposomes with neutrophils, generating oxygen-carrying sonosensitizer cells with acoustic functions, which are called Acouscyte/O2 , for the visual diagnosis and treatment of cancer. Specifically, oxygen-carried perfluorocarbon and temoporfin are encapsulated into cRGD peptide modified multilayer liposomes (C-ML/HPT/O2 ), which are then loaded into live neutrophils to obtain Acouscyte/O2 . Acouscyte/O2 can not only carry a large amount of oxygen but also exhibits the ability of long circulation, inflammation-triggered recruitment, and decomposition. Importantly, Acouscyte/O2 can be selectively accumulated in tumors, effectively enhancing tumor oxygen levels, and triggering anticancer sonodynamics in response to ultrasound stimulation, leading to complete obliteration of tumors and efficient extension of the survival time of tumor-bearing mice with minimal systemic adverse effects. Meanwhile, the tumors can be monitored in real time by temoporfin-mediated fluorescence imaging and perfluorocarbon (PFC)-microbubble-enhanced ultrasound imaging. Therefore, the nanoengineered neutrophils, i.e., Acouscyte/O2 , are a new type of multifunctional cellular drug, which provides a new platform for the diagnosis and sonodynamic therapy of solid malignant tumors.

The use of myristic acid as a ligand of polyethylenimine/DNA nanoparticles for targeted gene therapy of glioblastoma.

To establish a gene delivery system for brain targeting, a low molecular weight polyethylenimine (PEI(10 K)) was modified with myristic acid (MC), and complexed with DNA, yielding MC-PEI(10 K)/DNA nanoparticles successfully. The nanoparticles were observed to be successfully taken up by the brains of mice. The transfection efficiency of the nanoparticles was then investigated, and both the in vitro and in vivo gene expression of MC-PEI(10 K)/DNA nanoparticles is significantly higher than that of unmodified PEI(10 K)/DNA nanoparticles. The anti-glioblastoma effect of MC-PEI(10 K)/pORF-hTRAIL was demonstrated by the survival time of intracranial U87 glioblastoma-bearing mice. The median survival time of the MC-PEI(10 K)/pORF-hTRAIL group (28 days) was significantly longer than that of the PEI(10 K)/pORF-hTRAIL group (24 days), the MC-PEI(10 K)/pGL(3) group (21 days) and the saline group (22 days). Therefore, our results suggested that MC-PEI(10 K) could be potentially used for brain-targeted gene delivery and in the treatment of glioblastoma.

LyP-1-conjugated doxorubicin-loaded liposomes suppress lymphatic metastasis by inhibiting lymph node metastases and destroying tumor lymphatics.

Lymphatic metastasis can be greatly promoted by metastases growth and lymphangiogenesis in lymph nodes (LNs). LyP-1, a cyclic peptide, is able to specifically bind with tumor cells and tumor lymphatics in metastatic LNs. This work aimed to use LyP-1-conjugated liposomes (L-LS) loaded with doxorubicin (DOX) (L-LS/DOX) to suppress lymphatic metastasis by inhibiting both metastases and tumor lymphatics in LNs. L-LS were prepared and exhibited sizes around 90 nm and spherical morphology as characterized by transmission electron microscopy. The in vitro cellular studies showed that LyP-1 modification obviously increased liposome uptake by MDA-MB-435 tumor cells and enhanced the cytotoxicity of liposomal DOX. A popliteal and iliac LN metastases model was successfully established by subcutaneous inoculation of tumor cells to nude mice. The immunofluorescence staining analysis indicated that LyP-1 modification enabled specific binding of liposome with tumor lymphatics and enhanced the destroying effect of liposomal DOX on tumor lymphatics. The in vivo fluorescence imaging and pharmacodynamic studies showed that LyP-1 modification increased liposome uptake by metastatic LNs and that L-LS/DOX significantly decreased metastatic LN growth and LN metastasis rate. These results suggested that L-LS/DOX were an effective delivery system for suppressing lymphatic metastasis by simultaneously inhibiting LN metastases and tumor lymphatics.

SIRT2-knockdown rescues GARS-induced Charcot-Marie-Tooth neuropathy.

Charcot-Marie-Tooth disease is the most common inherited peripheral neuropathy. Dominant mutations in the glycyl-tRNA synthetase (GARS) gene cause peripheral nerve degeneration and lead to CMT disease type 2D. The underlying mechanisms of mutations in GARS (GARSCMT2D ) in disease pathogenesis are not fully understood. In this study, we report that wild-type GARS binds the NAD+ -dependent deacetylase SIRT2 and inhibits its deacetylation activity, resulting in the acetylated α-tubulin, the major substrate of SIRT2. The catalytic domain of GARS tightly interacts with SIRT2, which is the most CMT2D mutation localization. However, CMT2D mutations in GARS cannot inhibit SIRT2 deacetylation, which leads to a decrease of acetylated α-tubulin. Genetic reduction of SIRT2 in the Drosophila model rescues the GARS-induced axonal CMT neuropathy and extends the life span. Our findings demonstrate the pathogenic role of SIRT2-dependent α-tubulin deacetylation in mutant GARS-induced neuropathies and provide new perspectives for targeting SIRT2 as a potential therapy against hereditary axonopathies.

Loop 2 of Ophiophagus hannah toxin b binds with neuronal nicotinic acetylcholine receptors and enhances intracranial drug delivery.

Three-finger snake neurotoxins have been widely investigated for their high binding affinities with nicotinic acetylcholine receptors (nAChRs), which are widely expressed in the central nervous system including the blood-brain barrier and thus mediate intracranial drug delivery. The loop 2 segments of three-finger snake neurotoxins are considered as the binding domain with nAChRs, and thus, they may have the potential to enhance drug or drug delivery system intracranial transport. In the present work, binding of the synthetic peptides to the neuronal nAChRs was assessed by measuring their ability to inhibit the binding of (125)I-α-bungarotoxin to the receptor. The loop 2 segment of Ophiophagus hannah toxin b (KC2S) showed high binding affinity, and the competitive binding IC(50) value was 32.51 nM. Furthermore, the brain targeting efficiency of KC2S had been investigated in vitro and in vivo. The specific uptake by brain capillary endothelial cells (BCECs) demonstrated that KC2S could be endocytosized after binding with nAChRs. In vivo, the qualitative and quantitative biodistribution results of fluorescent dyes (DiR or coumarin-6) indicated that KC2S modified poly(ethylene glycol)-poly(lactic acid) micelles (KC2S-PEG-PLA micelles) could enhance intracranial drug delivery. Furthermore, intravenous treatment with paclitaxel-encapsulated KC2S-PEG-PLA micelles (KC2S-PEG-PLA-PTX micelles) afforded robust inhibition of intracranial glioblastoma. The median survival time of KC2S-PEG-PLA-PTX-micelle-treated mice (47.5 days) was significantly longer than that of mice treated by mPEG-PLA-PTX micelles (41.5 days), Taxol (38.5 days), or saline (34 days). Compared with the short peptide derived from rabies virus glycoprotein (RVG29) that has been previously reported as an excellent brain targeting ligand, KC2S has a similar binding affinity with neuronal nAChRs but fewer amino acid residues. Thus, we concluded that the loop 2 segment of Ophiophagus hannah toxin b could bind with neuronal nAChRs and thus enhance intracranial drug delivery for the treatment of central nervous system diseases.

TMC1 and TMC2 Proteins Are Pore-Forming Subunits of Mechanosensitive Ion Channels.

Transmembrane channel-like (TMC) 1 and 2 are required for the mechanotransduction of mouse inner ear hair cells and localize to the site of mechanotransduction in mouse hair cell stereocilia. However, it remains unclear whether TMC1 and TMC2 are indeed ion channels and whether they can sense mechanical force directly. Here we express TMC1 from the green sea turtle (CmTMC1) and TMC2 from the budgerigar (MuTMC2) in insect cells, purify and reconstitute the proteins, and show that liposome-reconstituted CmTMC1 and MuTMC2 proteins possess ion channel activity. Furthermore, by applying pressure to proteoliposomes, we demonstrate that both CmTMC1 and MuTMC2 proteins can indeed respond to mechanical stimuli. In addition, CmTMC1 mutants corresponding to human hearing loss mutants exhibit reduced or no ion channel activity. Taken together, our results show that the CmTMC1 and MuTMC2 proteins are pore-forming subunits of mechanosensitive ion channels, supporting TMC1 and TMC2 as hair cell transduction channels.

Amorphous Manganese Dioxide Coated Polydopamine Nanoparticles for Acid-Sensitive Magnetic Resonance Imaging-Guided Tumor Photothermal Therapy.

Photothermal therapy (PTT) is a powerful technique for tumor ablation. However, there is a problem that PTT cannot accurately locate the tumor site, so it is easy to cause heat damage to the surrounding normal tissues. In this study, PEGylated amorphous manganese dioxide (MnO2) coated polydopamine (PDA) core-shell nanoparticles (PDA@MnO2-PEG) with regular morphology and uniform dimensions were prepared for acid-sensitive magnetic resonance imaging-guided tumor photothermal therapy. The results showed that amorphous MnO2 shell provided markedly acid-sensitive T1-weighted magnetic resonance imaging (MRI). The relaxation rate (r1 value) of PDA@MnO2-PEG in pH=7.4 was measured to be 0.310 mM-1·S-1, while that in pH=6 became 4.364 mM-1·S-1. In mice tumor models, MRI of tumors exhibited dramatically whitening effects compared with the signal before injection. Besides, the in vivo experiments revealed that the tumors in PTT group with PDA@MnO2-PEG injection and NIR laser irradiation were almost eliminated within 14 days, indicating the effective photothermal therapy of tumor generated by the PDA core. In conclusion, we successfully synthesized amorphous MnO2 coated PDA core-shell nanoparticles with the function of acid-sensitive magnetic resonance imaging guided photothermal therapy, which provide a new approach for improving the effect of photothermal therapy of tumors.

Children's Empathy and Their Perception and Evaluation of Facial Pain Expression: An Eye Tracking Study.

The function of empathic concern to process pain is a product of evolutionary adaptation. Focusing on 5- to 6-year old children, the current study employed eye-tracking in an odd-one-out task (searching for the emotional facial expression among neutral expressions, N = 47) and a pain evaluation task (evaluating the pain intensity of a facial expression, N = 42) to investigate the relationship between children's empathy and their behavioral and perceptual response to facial pain expression. We found children detected painful expression faster than others (angry, sad, and happy), children high in empathy performed better on searching facial expression of pain, and gave higher evaluation of pain intensity; and rating for pain in painful expressions was best predicted by a self-reported empathy score. As for eye-tracking in pain detection, children fixated on pain more quickly, less frequently and for shorter times. Of facial clues, children fixated on eyes and mouth more quickly, more frequently and for longer times. These results implied that painful facial expression was different from others in a cognitive sense, and children's empathy might facilitate their search and make them perceive the intensity of observed pain on the higher side.