Effect of nano-selenium loaded with lycium barbarum polysaccharide on the proliferation of lens epithelial cells after UVB damage in vitro

AIM: To investigate the effect of nano-selenium loaded with different concentrations of lycium barbarum polysaccharide (LBP-SeNPs) on the proliferation of human lens epithelial cells (HLECs) from UV irradiation. METHODS: LBP-SeNPs were prepared and their particle size was detected. HLECs (SRA01/04) were irradiated with UVB for different time (0, 10, 20, 30, 40, 50, 60min) to construct a damaged model, the survival rate of cells was determined by methylthiazol tetrazolium (MTT) assay. The 4',6-Diamidine-2'-phenylindole dihydrochloride (DAPI) staining was used to observe the status of cell nucleus and drug entering cytoplasm through cell membrane in SRA01/04 cells after adding LBP-SENPS loaded with coumarin fluorescence agent 24h under fluorescence microscope. SRA01/04 normal and UVB-damaged cells were treated with different amounts of LBP-SeNPs at different concentrations, cells proliferation were observed. RESULTS: The particle size of LBP-SeNPs was stable in the range of 150-200 nm. The survival rate changes with time after UVB irradiation were statistically significant. The 10min of UVB exposure as the time was chosen to construct the cell damage model. With DAPI staining, LBP-SeNPs were observed to enter the cytoplasm through the cell membrane under fluorescence inverted microscope. Cytotoxicity of SRA01/04 at different concentrations of LBP-SeNPs were measured. Cell survival rate was statistically different compared with the control group. The higher the loading concentration of LBP in nano-Se drugs was, the higher the cell proliferation rate was (P<0.05). The lower the concentration of LBP-SeNPs, the higher the cell proliferation rate, showing a negative growth trend (P<0.05). The group with the highest average cell proliferation rate was 0.5 µmol/L 2.0 mg/mL LBP-SeNPs (128.80%). When the 2.0 mg/mL LBP-SeNPs group was selected for cell photography, the cell density was higher at 0.5 μmol/L. With the increase of concentration, SRA01/04 cells appeared more cytoplasm dehydration, cell shrinkage and apoptotic bodies, and cell density decreased. CONCLUSION: LBP-SeNPs has moderate particle size and good stability. LBP-SeNPs can protect HLECs (SRA01/04) from UVB-induced damage, and the cell proliferation rate is further increased with increasing the amount of loaded LBP and decreasing nano-selenium concentration.

The Role of Cell Membranes in Cell Traffic

The cell membrane plays an important role in cell traffic because it functions to secrete various molecules. The selective transport system allows the movement of molecules into or out of the cell compartment. By controlling the movement of substances from one compartment to another, membranes exert a strong influence on metabolic pathways. Cell membranes are composed of proteins and lipids with a very important function in maintaining the rhythm of circulation and cell transport. In addition, the cell membrane also plays a role in maintaining the integrity and relationship, and communication of cells.

An Original Approach to Measure Ligand/receptor Binding Affinity in Non-purified Samples

Several biochemical and biophysical methods are available to determine dissociation constants between a biological target and its ligands. Most of them require purification, labelling or surface immobilisation. However, these measurements remain challenging concerning membrane proteins because purification requires their extraction from the native lipid environment using different approaches, a process that may impact receptor conformation and functionality. We have developed a novel experimental procedure to determine binding affinities of a ligand to a membrane protein, the dopamine D2 receptor (D2R), directly from cell membrane fragments, using microscale thermophoresis (MST). Two main challenges had to be overcome: to determine the concentration of dopamine D2R in the crude sample; to find ways to minimize or account for non-specific binding of the ligand to cell fragments. Using MST, we were able to determine the D2R concentration in cell membrane fragments to be about 36.8 ± 2.6 pmol/mg. Then titration curves allowed the determination of a KD about 5.3 ± 1.7 nM, that is very close to the reported value. Important details of the experimental procedure are detailed to allow the transposition of this novel method to various membrane proteins.

Non-Cavitation Targeted Microbubble-Mediated Single-Cell Sonoporation

Sonoporation employs ultrasound accompanied by microbubble (MB) cavitation to induce the reversible disruption of cell membranes and has been exploited as a promising intracellular macromolecular delivery strategy. Due to the damage to cells resulting from strong cavitation, it is difficult to balance efficient delivery and high survival rates. In this paper, a traveling surface acoustic wave (TSAW) device, consisting of a TSAW chip and a polydimethylsiloxane (PDMS) channel, was designed to explore single-cell sonoporation using targeted microbubbles (TMBs) in a non-cavitation regime. A TSAW was applied to precisely manipulate the movement of the TMBs attached to MDA-MB-231 cells, leading to sonoporation at a single-cell level. The impact of input voltage and the number of TMBs on cell sonoporation was investigated. In addition, the physical mechanisms of bubble cavitation or the acoustic radiation force (ARF) for cell sonoporation were analyzed. The TMBs excited by an ARF directly propelled cell membrane deformation, leading to reversible perforation in the cell membrane. When two TMBs adhered to the cell surface and the input voltage was 350 mVpp, the cell sonoporation efficiency went up to 83%.

The interplay between membrane topology and mechanical forces in regulating T cell receptor activity

T cells are critically important for host defense against infections. T cell activation is specific because signal initiation requires T cell receptor (TCR) recognition of foreign antigen peptides presented by major histocompatibility complexes (pMHC) on antigen presenting cells (APCs). Recent advances reveal that the TCR acts as a mechanoreceptor, but it remains unclear how pMHC/TCR engagement generates mechanical forces that are converted to intracellular signals. Here we propose a TCR Bending Mechanosignal (TBM) model, in which local bending of the T cell membrane on the nanometer scale allows sustained contact of relatively small pMHC/TCR complexes interspersed among large surface receptors and adhesion molecules on the opposing surfaces of T cells and APCs. Localized T cell membrane bending is suggested to increase accessibility of TCR signaling domains to phosphorylation, facilitate selective recognition of agonists that form catch bonds, and reduce noise signals associated with slip bonds.

Bioinspired Membrane-Coated Nanoplatform for Targeted Tumor Immunotherapy

Immunotherapy can effectively activate the immune system and reshape the tumor immune microenvironment, which has been an alternative method in cancer therapy besides surgery, radiotherapy, and chemotherapy. However, the current clinical outcomes are not satisfied due to the lack of targeting of the treatment with some unexpected damages to the human body. Recently, cell membrane-based bioinspired nanoparticles for tumor immunotherapy have attracted much attention because of their superior immune regulating, drug delivery, excellent tumor targeting, and biocompatibility. Together, the article reviews the recent progress of cell membrane-based bioinspired nanoparticles for immunotherapy in cancer treatment. We also evaluate the prospect of bioinspired nanoparticles in immunotherapy for cancer. This strategy may open up new research directions for cancer therapy.

Homologous tumor cell membrane vesicles active preferential self-recognition of tumor cells in vitro

Cell membrane vesicles, as delivery carriers of drugs or biological agents in vivo, are an important therapeutic mode in the study of disease treatment. Tumor membrane-derived vesicles have been widely used in tumor therapy because of their good tumor enrichment effect. The most common method is the surface of nanoparticles coated with tumor cell membrane, which can effectively prolong the circulation time of particles in the blood and the enrichment of tumors. In this study, we prepared vesicles of different tumor cell membrane derivate and studied their targeting to tumors detailly. The results showed that homologous vesicles have high targeting to homologous tumor cells. The fluorescence of vesicles in homologous tumor cells was significantly higher than that in other tumor cells. This study will provide a new strategy and guidance for the clinical treatment of cancer based on the tumor cell membrane system. Graphical Abstract