Protein Transduction System Based on Tryptophan-zipper against Intracellular Infections via Inhibiting Ferroptosis of Macrophages.

Cells penetrating molecules in living systems hold promise of capturing and eliminating threats and damage that can plan intracellular fate promptly. However, it remains challenging to construct cell penetration systems that are physiologically stable with predictable self-assembly behavior and well-defined mechanisms. In this study, we develop a core-shell nanoparticle using a hyaluronic acid (HA)-coated protein transduction domain (PTD) derived from the human immunodeficiency virus (HIV). This nanoparticle can encapsulate pathogens, transporting the PTD into macrophages via lipid rafts. PTD forms hydrogen bonds with the components of the membrane through TAT, which has a high density of positive charges and reduces the degree of membrane order through Tryptophan (Trp)-zipper binding to the acyl tails of phospholipid molecules. HA-encapsulated PTD increases the resistance to trypsin and proteinase K, thereby penetrating macrophages and eliminating intracellular infections. Interestingly, the nonagglutination mechanism of PTD against pathogens ensures the safe operation of the cellular system. Importantly, PTD can activate the critical pathway of antiferroptosis in macrophages against pathogen infection. The nanoparticles developed in this study demonstrate safety and efficacy against Gram-negative and Gram-positive pathogens in three animal models. Overall, this work highlights the effectiveness of the PTD nanoparticle in encapsulating pathogens and provides a paradigm for transduction systems-anti-intracellular infection therapy.

Circ_0110498 facilitates the cisplatin resistance of non-small cell lung cancer by mediating the miR-1287-5p/RBBP4 axis.

BACKGROUND: Circular RNAs (circRNAs) play vital roles in non-small cell lung cancer (NSCLC) progression. Our research analyzed the role of circ_0110498 on the cisplatin (DDP) resistance of NSCLC. METHODS: Cell glycolysis was analyzed by measuring glucose consumption and lactate production. Protein expression was determined by western blot analysis. The expression of circ_0110498, microRNA (miR)-1287-5p and RBBP4 was detected by RT-qPCR assay. Cell counting kit-8, colony formation and transwell assays, together with flow cytometry were conducted to analyze cell DDP resistance, proliferation, metastasis and apoptosis. RESULTS: Circ_0110498 expression was elevated in DDP-resistant NSCLC tissues and cells. Circ_0110498 silencing not only suppressed the DDP resistance of NSCLC cells by inhibiting cell growth, metastasis and glycolysis, but also enhanced the DDP sensitivity of NSCLC tumors. MiR-1287-5p was sponged by circ_0110498, and its inhibitor also reversed the effect of circ_0110498 silencing on the DDP resistance of NSCLC cells. MiR-1287-5p interacted with RBBP4, and RBBP4 overexpression partly reversed the inhibitory effect of miR-1287-5p on the DDP resistance of NSCLC cells. CONCLUSION: Circ_0110498 facilitated DDP resistance partly through mediating the miR-1287-5p/RBBP4 signaling in NSCLC.

Bioinformatic Analysis Identifies of Potential miRNA-mRNA Regulatory Networks Involved in the Pathogenesis of Lung Cancer.

Objective: The purpose of the present study was to explore the biomarkers related to lung cancer based on the bioinformatics method, which might be new targets for lung cancer treatment. Methods: GSE17681 and GSE18842 were obtained from the Gene Expression Omnibus (GEO) database. The differentially expressed miRNAs (DEMs) and genes (DEGs) in lung cancer samples were screened via the GEO2R online tool. DEMs were submitted to the mirDIP website to predict target genes. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis were conducted via uploading DEGs to the DAVID database. The protein-protein interaction network (PPI) of the DEGs was analyzed by STRING's online tool. Then, the PPI network was visualized using Cytoscape 3.8.0. Results: 46 DEMs were identified in GSE17681, and the website predicted that there were 873 target genes of these DEMs. 1029 DEGs were identified in the GSE18842 chip. GO analysis suggested that the co-DEGs participated in the canonical Wnt signaling pathway, regulation of the Wnt signaling pathway, a serine/threonine kinase signaling pathway, the Wnt signaling pathway, and cell-cell signaling by Wnt. KEGG analysis results showed the co-DEGs of GSE17681 and GSE18842 were related to the Hippo signaling pathway and adhesion molecules. In addition, six hub genes that were related to lung cancer were identified as hub genes, including mTOR, NF1, CHD7, ETS1, IL-6, and COL1A1. Conclusions: The present study identified six hub genes that were related to lung cancer, including mTOR, NF1, CHD7, ETS1, IL-6, and COL1A1, which might be a potential target for lung cancer.

Structural Reorganization of a Synthetic Mimic of the Oxygen-Evolving Center in Multiple Redox Transitions Revealed by Electrochemical FTIR Spectra.

In photosynthesis, the protein-bound natural oxygen-evolving center (OEC) undergoes multiple oxidation-state transitions in the light-driven water splitting reactions with a stepwise change in the oxidation potential. Because the protein is vulnerable to electrochemical oxidation, the multiple oxidation/reduction-state transitions can hardly be achieved by electrochemical oxidation with a continuous change in the oxidation potential. An OEC mimic that can undergo four redox transitions has been synthesized (Zhang, C., Science, 2015, 348, 690-693). Here we report an electrochemical FTIR spectroscopic study of this synthetic complex at its multiple oxidation states in the low-frequency region for Mn-O bonds. Compared with those of the native OEC induced by pulsed laser flashes, our results also show the existence of two structural isomers in the S2 state, with the closed cubane conformer being more stable than the open cubane conformer, in contrast to that of the native OEC in which the open form is more stable.

Hsa_circ_0069244 acts as the sponge of miR-346 to inhibit non-small cell lung cancer progression by regulating XPC expression.

Circular RNAs (circRNAs) play a significant role in the progression of diverse malignancies. Here, we aimed to probe the function and mechanism of circ_0069244 in non-small cell lung cancer (NSCLC). In the present study, circ_0069244 was selected from the circRNA microarray datasets (GSE112214). Quantitative real-time polymerase chain reaction (qRT-PCR) was applied to examine circ_0069244, miR-346 and XPC complex subunit, DNA damage recognition and repair factor (XPC) expression levels. Kaplan-Meier curve was employed to analyze the association between circ_0069244 expression and overall survival of NSCLC patients. Cell counting kit-8 (CCK-8) and 5-Bromo-2'-deoxyuridine (BrdU) experiments were utilized to examine the proliferation of NSCLC cells. Scratch healing and Transwell experiments were executed to examine the migration of NSCLC cells. Western blot was conducted to detect XPC expression at protein level in NSCLC cells. Bioinformatics analysis, dual-luciferase reporter gene and RNA immunoprecipitation (RIP) experiments predicted and validated the targeting relationships of circ_0069244 and miR-346, as well as miR-346 and 3'untranslated region (UTR) of XPC mRNA, respectively. We reported that circ_0069244 was remarkably down modulated in NSCLC and was linked to shorter survival and poor tumor histological grade in NSCLC patients. Functionally, circ_0069244 repressed NSCLC cell proliferation and migration. Furthermore, miR-346-5p was unveiled to be a downstream target of circ_0069244, and miR-346-5p specifically modulated XPC expression. Rescue experiments indicated that the inhibitory effect of circ_0069244 was abolished by co-expression of miR-346-5p mimics. Taken together, circ_0069244 restrained NSCLC progression by modulating the miR-346-5p/XPC axis.

Circ_0006988 promotes the proliferation, metastasis and angiogenesis of non-small cell lung cancer cells by modulating miR-491-5p/MAP3K3 axis.

Circular RNAs (circRNAs) are related to the progression of non-small cell lung cancer (NSCLC). However, the roles and mechanism of circ_0006988 are largely unknown. The levels of circ_0006988, Low-Density Lipoprotein Receptor Class A Domain Containing 3 (LDLRAD3), microRNA-491-5p (miR-491-5p), Mitogen-Activated Protein Kinase Kinase Kinase 3 (MAP3K3) were measured using quantitative real-time polymerase-chain reaction (qRT-PCR) and western blot assay. The characteristic of circ_0006988 was analyzed by RNase R assay and Actinomycin D assay. Functional analyses were processed by Cell Counting Kit-8 (CCK-8) assay, 5-ethynyl-2'-deoxyuridine (EdU) assay, colony formation assay, flow cytometry analysis, transwell assay, wound-healing assay and tube formation assay. The interactions between circ_0006988 and miR-491-5p as well as miR-491-5p and MAP3K3 were analyzed by dual-luciferase reporter assay and RNA immunoprecipitation (RIP) assay. Murine xenograft model assay was processed to verify the function of circ_0006988 in vivo. Immunohistochemistry (IHC) assay was conducted to examine the level of Ki67. Circ_0006988 abundance was increased in NSCLC tissues and cells. Circ_0006988 silencing restrained NSCLC cell proliferation, migration, invasion and angiogenesis, and induced apoptosis. Circ_0006988 sponged miR-491-5p, which directly targeted MAP3K3. MiR-491-5p overexpression repressed NSCLC cell malignant behaviors. MiR-491-5p downregulation or MAP3K3 overexpression reversed the effect of circ_0006988 silencing on NSCLC cell progression. In addition, circ_0006988 knockdown reduced xenograft tumor growth. ssCirc_0006988 contributed to the development of NSCLC by miR-491-5p/MAP3K3 axis.

Baicalin alleviates chronic obstructive pulmonary disease through regulation of HSP72-mediated JNK pathway.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) is characterized by airway obstruction and progressive lung inflammation. As the primary ingredient of a traditional Chinese medical herb, Baicalin has been previously shown to possess anti-inflammatory abilities. Thus, the current study aimed to elucidate the mechanism by which baicalin alleviates COPD. METHODS: Baicalin was adopted to treat cigarette smoke in extract-exposed MLE-12 cells after which cell viability and apoptosis were determined. The production of tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6), IL-8 were determined by enzyme-linked immunoassay. A COPD mouse model was constructed via exposure to cigarette smoke and lipopolysaccharide, baicalin treatment. Lung function and inflammatory cell infiltration were determined and the production of Muc5AC, TNF-α, IL-6, IL-8 in the bronchoalveolar lavage fluid (BALF) was assayed by ELISA. The effect of HSP72 and JNK on COPD following treatment with baicalin was assessed both in vivo and in vitro by conducting loss- and gain- function experiments. RESULTS: Baicalin improved lung function evidenced by reduction in inflammatory cell infiltration and Muc5AC, TNF-α, IL-6 and IL-8 levels observed in BALF in mice. Baicalin was further observed to elevate cell viability while inhibited apoptosis and TNF-α, IL-6 and IL-8 levels in MLE-12 cells. Baicalin treatment increased HSP72 expression, while its depletion reversed the effect of baicalin on COPD. HSP72 inhibited the activation of JNK, while JNK activation was found to inhibit the effect of baicalin on COPD. CONCLUSIONS: Baicalin upregulated the expression of HSP72, resulting in the inhibition of JNK signaling activation, which ultimately alleviates COPD.

KLF5-induced BBOX1-AS1 contributes to cell malignant phenotypes in non-small cell lung cancer via sponging miR-27a-5p to up-regulate MELK and activate FAK signaling pathway.

BACKGROUND: Non-small cell lung cancer (NSCLC) is a major histological subtype of lung cancer with high mortality and morbidity. A substantial amount of evidence demonstrates long non-coding RNAs (lncRNA) as critical regulators in tumorigeneis and malignant progression of human cancers. The oncogenic role of BBOX1 anti-sense RNA 1 (BBOX1-AS1) has been reported in several tumors. As yet, the potential functions and mechanisms of BBOX1-AS1 in NSCLC are obscure. METHODS: The gene and protein expression was detected by qRT-PCR and western blot. Cell function was determined by CCK-8, colony forming, would healing and transwell assays. Bioinformatics tools, ChIP assays, dual luciferase reporters system and RNA pull-down experiments were used to examine the interaction between molecules. Subcutaneous tumor models in nude mice were established to investigate in vivo NSCLC cell behavior. RESULTS: BBOX1-AS1 was highly expressed in NSCLC tissues and cells. High BBOX1-AS1 expression was associated with worse clinical parameters and poor prognosis. BBOX1-AS1 up-regulation was induced by transcription factor KLF5. BBOX1-AS1 deficiency resulted in an inhibition of cell proliferation, migration, invasion and EMT in vitro. Also, knockdown of BBOX1-AS1 suppressed NSCLC xenograft tumor growth in mice in vivo. Mechanistically, BBOX1-AS1 acted act as a competetive "sponge" of miR-27a-5p to promote maternal embryonic leucine zipper kinase (MELK) expression and activate FAK signaling. miR-27a-5p was confirmed as a tumor suppressor in NSCLC. Moreover, BBOX1-AS1-induced increase of cell proliferation, migration, invasion and EMT was greatly reversed due to the overexpression of miR-27a-5p. In addition, the suppressive effect of NSCLC progression owing to BBOX1-AS1 depletion was abated by the up-regulation of MELK. Consistently, BBOX1-AS1-mediated carcinogenicity was attenuated in NSCLC after treatment with a specific MELK inhibitor OTSSP167. CONCLUSIONS: KLF5-induced BBOX1-AS1 exerts tumor-promotive roles in NSCLC via sponging miR-27a-5p to activate MELK/FAK signaling, providing the possibility of employing BBOX1-AS1 as a therapeutic target for NSCLC patients.

Membrane protein density determining membrane fusion revealed by dynamic fluorescence imaging.

Membrane fusion is fundamental to biological activity of cells, so disclosingits relevant mechanism is very important for understanding various cell functions. Although artificial model systems have been developed to uncover the mechanism of membrane fusion, key factors determining the mode of membrane fusion remain unclear. Based on the construction of different types of liposome vesicles, we used a dynamic fluorescence imaging method to investigate the effect of membrane protein distribution density on membrane fusion. Time-resolved imaging revealed that protein-free pure phospholipid vesicles themselves occurred full membrane fusion. Moreover, we prepared proteoliposomes with increasing protein-to-lipid ratio to better reflect the characteristic of membrane structure in vivo. Our data showed that pure phospholipid vesicles no longer fused with the proteoliposomes that in a higher protein proportion, indicating dense membrane proteins may hinder membrane fusion. A further comparative analysis of the interactions of pure phospholipid vesicles with the cell membrane / giant plasma membrane vesicles (GPMVs) / protein-free giant unilamellar vesicles (GUVs) confirmed the inhibitory effect of dense membrane proteins on membrane fusion. Our work demonstrates the membrane protein density influences the mode of membrane fusion and lays a foundation for constructing quasi-native membrane fusion models in vitro.

Ganoderic acid B attenuates LPS-induced lung injury.

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a serious respiratory disease, the mechanism is unclear. This paper revealed the mechanism of ganoderic acid B (BB) on lipopolysaccharide-induced pneumonia in mice. Pneumonia model was induced by LPS in mice and A549 cells. Lung dry/wet weight (W/D) and myeloperoxidase (MPO) activity in lung were examined. Lung histopathological changes was observed by HE staining. Superoxide dismutase (SOD), malondialdehyde (MDA) and proinflammatory cytokines, including tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß) and interleukin-6 (IL-6) in mice and A549 cells were detected. Rho/NF-κB pathway in mice and A549 cells were examined by Western Blot. BB significantly reduced W/D and MPO activity, restored lung histopathological changes. BB also increased SOD, decreased MDA, TNF-α, IL-1ß and IL-6 in mice and A549 cells. In addition, BB inhibited Rho/NF-κB pathway in mice and A549 cells. BB has protective effect on LPS-induced pneumonia in mice, and its mechanism is related to the regulation of Rho/NF-κB signaling pathway.

Application of an inhibitor-based probe to reveal the distribution of membrane PSMA in dSTORM imaging.

Relying on an inhibitor-based probe, we reveal the clustered distribution of membrane PSMA by dSTORM imaging and uncover its potential interaction with folate receptor. This inhibitor-based strategy realizes more accurate labeling than antibody labeling, which would make it a powerful tool in the field of dSTORM imaging.

Aptamer AS1411 utilized for super-resolution imaging of nucleolin.

Nucleolin (NCL) is a multifunctional protein that mainly localizes in the nucleolus and also distributes in the nucleoplasm, cytoplasm and cell membrane. Most studies focus on its biofunctions in cell activities and diseases, however, its detailed distribution and organization pattern in situ remains obscure. Moreover, antibodies were commonly used to investigate NCL in cells. It is worth noting that antibody labeling of intracellular proteins needs detergents to permeabilize the membrane, which could disrupt the membrane structure and proteins. The emergence of aptamer AS1411 provides us a good choice to recognize the NCL without permeabilization owing to its superior cellular uptake and enhanced stability. Therefore, we applied aptamer AS1411 to super-resolution imaging to visualize the distribution of NCL at a nanometer level. Aptamer achieved a better recognition of intracellular NCL and displayed the detailed structure of NCL in different parts of cells. Significantly, cytoplasmic and membrane NCL have higher expression and larger clusters in cancer cells than that in normal cells. Our work presented a detailed organization of NCL in cells and revealed the distribution differences between cancer cells and normal cells, which promote the understanding of its functions in physiology and pathology.

Correlative dual-color dSTORM/AFM reveals protein clusters at the cytoplasmic side of human bronchial epithelium membranes.

The organization of a cell membrane is vital for various functions, such as receptor signaling and membrane traffic. However, the understanding of membrane organization remains insufficient, especially the localizations of specific proteins in the cell membrane. Here, we used correlative super-resolution fluorescence/atomic force microscopy to correlate the distributions of specific proteins Na+/K+-ATPase (NKA, an integral membrane protein) and ankyrin G (AnkG, a scaffolding protein) with the topography of the cytoplasmic side of human bronchial epithelium membranes. Our data showed that NKA and AnkG proteins preferred to localize in the protein islands of membranes. Interestingly, we also found that functional domains composed of specific proteins with a few hundreds of nanometers were formed by assembling protein islands with a few tens of nanometers.

Mechanical force regulation of YAP by F-actin and GPCR revealed by super-resolution imaging.

The Hippo signaling pathway plays critical roles in many biological processes including mechanotransduction. The key activator YAP of this pathway is considered as a central component of mechanotransduction signaling sensing the extracellular mechanical microenvironment changes, such as different cell density, the architecture of tissues and matrix stiffness. Although it has been largely studied that YAP is involved in these processes, the underlying mechanism of mechanical force-induced YAP regulation remains unclear. Here we exerted pressure on cell surfaces and investigated how YAP senses the extracellular mechanical force change using one of the super-resolution imaging techniques, dSTORM. We demonstrated that pressure promoted F-actin depolymerization, RhoA down-regulation, and LPAR1 (Gα12/13-coupled receptor) inactivation, which led to YAP cytoplasmic translocation and decreased clustering. Our work uncovers the role of GPCRs and F-actin in pressure-controlled YAP inactivation, and provides new insights into the mechanisms of mechanical regulation of the Hippo signaling pathway.

Quantitatively Mapping the Assembly Pattern of EpCAM on Cell Membranes with Peptide Probes.

Epithelial cell adhesion molecule (EpCAM) is an important type I transmembrane protein that is overexpressed on the surfaces of most cancer cells and involved in various biological processes such as cell adhesion and cell signaling. Although it plays crucial roles in cell functions and tumorigenesis, questions concerning the detailed morphology, molecular stoichiometry, and the assembly mechanisms of EpCAM on cell membranes have not been fully elucidated. Here, we used direct stochastic optical reconstruction microscopy (dSTORM) and relied on fluorophore-conjugated peptides to quantitatively analyze the assembly pattern of EpCAM with single-molecule precision. EpCAM was found to organize heterogeneous clusters with different sizes, which contain different numbers of EpCAM molecules on MCF-7 cell membranes. Moreover, dual-color dSTORM imaging revealed a significant correlation between EpCAM and tetraspanin CD9, and part of the EpCAM clusters could be disrupted by knockdown of CD9, which indicated that EpCAM might localize in tetraspanin-enriched microdomains (TEMs) and function cooperatively with CD9 on cell membranes. In addition, the assembly of the membrane EpCAM was found to be limited by both cytoskeleton and glycosylation. Overall, our work clarified the clustered distribution of EpCAM and revealed the potential mechanisms of its clustering at the molecular level, promoting a deeper understanding of the nano-organization of membrane proteins.

Positive PD-L1 expression is predictive for patients with advanced EGFR wild-type non-small cell lung cancer treated with gemcitabine and cisplatin.

This retrospective study aimed to investigate the association between programmed death ligand-1 (PD-L1) expression and the clinicopathological characteristics of patients with advanced epidermal growth factor receptor (EGFR) wild-type non-small cell lung cancer (NSCLC). The predictive role and cut-off value of PD-L1 expression was subsequently investigated. A total of 172 patients with advanced EGFR wild-type NSCLC were enrolled. All patients received platinum-based doublet chemotherapy (gemcitabine plus cisplatin). PD-L1 expression in lung tissues was assessed using immunohistochemical methods. The χ2 test was used to analyze the association between PD-L1 expression and clinicopathological characteristics. Survival time analysis was performed using the Kaplan-Meier method. The two groups, positive PD-L1 expression and negative PD-L1 expression, were compared using the log-rank test. Multivariate analysis using the Cox proportional hazard regression model was conducted to determine prognostic factors for overall survival (OS) and progression-free survival (PFS) times. Positive PD-L1 expression was observed in 48.3% (84/172), 40.7% (70/172), 21.5% (37/172) and 8.1% (14/172) of patients when using cut-off values of 1, 5, 10 and 50%, respectively. The χ2 test revealed that elevated pretreatment C-reactive protein (CRP) level and cancer stage IV were significantly associated with positive PD-L1 expression. The OS and PFS of positive PD-L1 (1, 5, 10 and 50% cut-off) expression group were shorter compared with the negative PD-L1 (1, 5, 10 and 50% cut-off) expression group. Multivariate survival analysis revealed that PD-L1 expression ≥50% was significantly associated with decreased OS and PFS [OS time, P=0.001; hazard ratio (HR), 2.768; 95% confidence interval (CI), 1.551-4.940; PFS time, P=0.002; HR, 2.537; 95% CI, 1.423-4.524]. These results indicated that positive PD-L1 (50% cut-off) expression was an independent predictor of poor prognosis for patients with advanced NSCLC treated with gemcitabine plus cisplatin. PD-L1 expression was associated with CRP level and cancer stage. The results obtained in the present study suggest that positive PD-L1 expression serves a prognostic role in advanced NSCLC and that the optimal cut-off value may be 50%.

Using an RNA aptamer probe for super-resolution imaging of native EGFR.

Aptamers, referred to as "chemical antibodies", are short single-stranded oligonucleotides that bind to targets with high affinity and specificity. Compared with antibodies, aptamers can be designed, developed and modified easily. Since their discovery, aptamers have been widely used in in vitro diagnostics and molecular imaging. However, they are relatively less studied and applied in advanced microscopy. Here we used an RNA aptamer in dSTORM imaging and obtained a high-quality image of EGFR nanoscale clusters on live cell membranes. The results showed that the cluster number and size with aptamer labeling were almost the same as those with labeling with the natural ligand EGF, but the morphology of the clusters was smaller and more regular than that with cetuximab labeling. Meanwhile, dual-color imaging demonstrated sufficient fluorophore labeling, highly specific recognition and greatly accurate clustering information provided by aptamers. Furthermore, the aptamer labeling method indicated that active EGFR formed larger clusters containing more molecules than resting EGFR, which was hidden under the antibody labeling. Our work suggested that aptamers can be used as versatile probes in super-resolution imaging with small steric hindrance, opening a new avenue for detailed and precise morphological analysis of membrane proteins.

Correction: Using an RNA aptamer probe for super-resolution imaging of native EGFR.

[This corrects the article DOI: 10.1039/C8NA00143J.].

Mechanistic insights into GLUT1 activation and clustering revealed by super-resolution imaging.

The glucose transporter GLUT1, a plasma membrane protein that mediates glucose homeostasis in mammalian cells, is responsible for constitutive uptake of glucose into many tissues and organs. Many studies have focused on its vital physiological functions and close relationship with diseases. However, the molecular mechanisms of its activation and transport are not clear, and its detailed distribution pattern on cell membranes also remains unknown. To address these, we first investigated the distribution and assembly of GLUT1 at a nanometer resolution by super-resolution imaging. On HeLa cell membranes, the transporter formed clusters with an average diameter of ∼250 nm, the majority of which were regulated by lipid rafts, as well as being restricted in size by both the cytoskeleton and glycosylation. More importantly, we found that the activation of GLUT1 by azide or MßCD did not increase its membrane expression but induced the decrease of the large clusters. The results suggested that sporadic distribution of GLUT1 may facilitate the transport of glucose, implying a potential association between the distribution and activation. Collectively, our work characterized the clustering distribution of GLUT1 and linked its spatial structural organization to the functions, which would provide insights into the activation mechanism of the transporter.

Antibacterial activities and molecular mechanism of amino-terminal fragments from pig nematode antimicrobial peptide CP-1.

High manufacturing costs and weak cell selectivity have limited the clinical application of naturally occurring peptides when faced with an outbreak of drug resistance. To overcome these limitations, a set of antimicrobial peptides was synthesized with the general sequence of (WL)n, where n = 1, 2, 3, and WL was truncated from the N-terminus of Cecropin P1 without initial serine residues. The antimicrobial peptide WL3 exhibited stronger antimicrobial activity against both Gram-negative and Gram-positive microbes than the parental peptide CP-1. WL3 showed no hemolysis even at the highest test concentrations compared to the parental peptide CP-1. The condition sensitivity assays (salts, serum, and trypsin) demonstrated that WL3 had high stability in vitro. Fluorescence spectroscopy and electron microscopy indicated that WL3 killed microbes by means of penetrating the membrane and causing cell lysis. In a mouse model, WL3 was able to significantly reduce the bacteria load in major organs and cytokines (TNF-α, IL-6, and IL-1ß) levels in serum. In summary, these findings suggest that WL3, which was modified from a natural antimicrobial peptide, has enormous potential for application as a novel antibacterial agent.