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Enveloped viruses such as SARS-CoV-2 frequently have a highly infectious nature and are considered effective natural delivery systems exhibiting high efficiency and specificity. Since simultaneously enhancing the activity and selectivity of lipopeptides is a seemingly unsolvable problem for conventional chemistry and pharmaceutical approaches, we present a biomimetic strategy to construct lipopeptide-based mimics of viral architectures and infections to enhance their antimicrobial efficacy while avoiding side effects. Herein, a surface-nanoengineered antimicrobial liposome (SNAL) is developed with the morphological features of enveloped viruses, including a moderate size range, lipid-based membrane structure, and highly lipopeptide-enriched bilayer surface. The SNAL possesses virus-like infection to bacterial cells, which can mediate high-efficiency and high-selectivity bacteria binding, rapidly attack and invade bacteria via plasma membrane fusion pathway, and induce a local “burst” release of lipopeptide to produce irreversible damage of cell membrane. Remarkably, viral mimics are effective against multiple pathogens with low minimum inhibitory concentrations (1.6–6.3 μg mL−1), high bactericidal efficiency of >99% within 2 h, >10-fold enhanced selectivity over free lipopeptide, 99.8% reduction in skin MRSA load after a single treatment, and negligible toxicity. This bioinspired design has significant potential to enhance the therapeutic efficacy of lipopeptides and may create new opportunities for designing next-generation antimicrobials., Graphical abstract Image 1

We have previously identified a novel non-selective membrane conductance (gsubUS/sub) opened by focused ultrasound (FUS) in crayfish motor axons. In the work described here, we studied gsubUS/subproperties further by comparing FUS-evoked depolarization (FUSD) in control and hypotonic saline with 75% of control osmolarity. The FUS was a train of 20 FUS bursts (2.1 MHz and 50 µs per burst) delivered at 1 kHz. The amplitude, onset latency, frequency of occurrence and duration of FUSD were compared in a 15-min time window before and after switching to hypotonic saline. Significant increases were observed for amplitude (plt; 0.001) and frequency of occurrence (plt; 0.01) while the onset latency exhibited a significant decrease (plt; 0.001). FUSD duration did not significantly differ. These results support predictions based on our hypothesis that gsubUS/subis mediated by opening of nanopores in the lipid bilayer and that stretching of axonal membrane caused by swelling at low osmolarity should increase the probability of nanopore formation under FUS. The FUSD parameters, in addition, exhibited time-dependent trends when the window of observation was expanded to 45 min in each saline. The statistical significance of amplitude and duration differed between 15- and 45-min time windows, indicating the presence of adaptive responses of axonal membrane to osmotic manipulation.

Extracellular signal-regulated kinase 8 (ERK8), also known as mitogen-activated protein kinase 15 (MAPK15), is the most recently identified protein kinase of the ERK family members and yet the least has been studied so far. Here, we report that ERK8 is highly expressed in several human lung cancer cell lines and is positively correlated with their sensitivities to the anti-cancer drug arsenic trioxide (As2O3). As2O3 at physiologically relevant concentrations (5-20 μM) potently stimulates the phosphorylation of ERK8 at Thr175 and Tyr177 within the TEY motif in the kinase domain, leading to its activation. Interestingly, activated ERK8 interacts and directly phosphorylates IkappaBalpha (IκBα) at Ser32 and Ser36, resulting in IκBα degradation. This in turn promotes nuclear factor-kappaB (NF-κB) p65 nuclear translocation and chromatin-binding, as well as the subsequent induction and activation of proteins involved in apoptosis. We also show that stable short-hairpin RNA-specific knockdown of endogenous ERK8 or inhibition of NF-κB activity by NF-κB inhibitor in high ERK8 expressing lung cancer H1299 cells blunted the As2O3-induced NF-κB activation and cytotoxicity towards these cells, indicating the critical role of ERK8 and NF-κB in mediating the As2O3 effects. Taken together, our findings suggest for the first time a regulatory paradigm of NF-κB activation by ERK8 upon As2O3 treatment in human lung cancer cells; and implicate a potential therapeutic advantage of As2O3 that might gain more selective killing of cancer cells with high ERK8 expression.

Protein drugs were considered to be the first choice to treat many human diseases, but their clinical application was usually limited by their short half-life and lack of validated targeted therapy. Here, a series of folate-functionalized poly(ethylene glycol)-b-(poly(2-aminoethyl-L-glutamate)-g-poly(L-glutamic acid))s (FA-PEG-b-(PELG-g-PLGA)s) were designed as tumor-targeted carriers for cationic protein delivery. Compared with traditional copolymers consisting of PEG and linear charged hydrophilic blocks, FA-PEG-b-(PELG-g-PLGA) with brush-like polyelectrolyte segments were beneficial to improving their electrostatic interactions with loading protein molecules, thus increasing drug-loading stability and protecting encapsulated proteins from degradation. The designed polymer brushes could efficiently encapsulate cytochrome C (CytC), a cationic model protein, to form polyion complex (PIC) micelles with an average particle size of approximately 200 nm. An in vitro drug release study showed that the drug-loading stability of the formed PIC micelles was largely improved. The functionalization of the block copolymer carriers with a targeting folate group enhanced the tumor cell growth inhibition and total apoptotic rates induced by CytC. Our results shed light on the unique advantages of brush-like polymer carriers in delivering cationic proteins, and the poly(L-glutamic acid)-based linear-brush diblock copolymers could be applied as a versatile delivery platform for molecular targeting in cancer therapy.

We report a novel phenomenon produced by focused ultrasound (US) that may be important for understanding its effects on cell membranes. When a US burst (2.1 MHz, 1-mm focal diameter, 0.1–1 MPa) was focused on a motor axon of the crayfish neuromuscular junction, it consistently produced a fast hyperpolarization, which was followed or superseded by subthreshold depolarizations or action potentials in a stochastic manner. The depolarization persisted in the presence of voltage-gated channel blockers [1 µM TTX ( INa), 50 µM ZD7288 ( Ih), and 200 µM 4-aminopyridine ( IK)] and typically started shortly after the onset of a 5-ms US burst, with a mean latency of 3.35 ± 0.53 ms (SE). The duration and amplitude of depolarizations averaged 2.13 ± 0.87 s and 10.1 ± 2.09 mV, with a maximum of 200 s and 60 mV, respectively. The US-induced depolarization was always associated with a decrease in membrane resistance. By measuring membrane potential and resistance during the US-induced depolarization, the reversal potential of US-induced conductance ( gus) was estimated to be −8.4 ± 2.3 mV, suggesting a nonselective conductance. The increase in gus was 10–100 times larger than the leak conductance; thus it could significantly influence neuronal activity. This change in conductance may be due to stimulation of mechanoreceptors. Alternatively, US may perturb the lateral motion of phospholipids and produce nanopores, which then increase gus. These results may be important for understanding mechanisms underlying US-mediated modulation of neuronal activity and brain function. NEW & NOTEWORTHY We report a specific increase in membrane conductance produced by ultrasound (US) on neuronal membrane. When a 5-ms US tone burst was focused on a crayfish motor axon, it stochastically triggered either depolarization or a spike train. The depolarization was up to 60 mV in amplitude and 200 s in duration and therefore could significantly influence neuronal activity. Depolarization was still evoked by US burst in the presence of Na+ and Ca2+ channel blockers and had a reversal potential of −8.4 ± 2.3 mV, suggesting a nonselective permeability. US can be applied noninvasively in the form of a focused beam to deep brain areas through the skull and has been shown to modulate brain activity. Understanding the depolarization reported here should be helpful for improving the use of US for noninvasive modulation and stimulation in brain-related disease.

// Xingmu Liu 1,2,* , Tao Huang 1,* , Xueling Chen 1 , Meiling Yan 1 , Feiyuan Yu 1 , Huan Gu 1 , Chao He 2 and Jiang Gu 1 1 Department of Pathology and Provincial Key Laboratory of Infectious Diseases and Immunopathology, Collaborative and Creative Center, Molecular Diagnosis and Personalized Medicine, Shantou University Medical College, Shantou, Guangdong, China 2 Department of General Surgery, Second Affiliated Hospital, Shantou University Medical College, Shantou, Guangdong, China * These authors have contributed equally to this work Correspondence to: Jiang Gu, email: // Keywords : immunoglobulin G, rat model, transplantation, rejection, cytokines, Immunology and Microbiology Section, Immune response, Immunity Received : February 25, 2016 Accepted : May 23, 2016 Published : June 05, 2016 Abstract Immunoglobulin G (IgG) has been shown to protect graft rejection after transplantation, whereas the molecular mechanism of IgG in promoting graft acceptance has not been well established. In this study, we tested the effectiveness of IgG in preventing rejection of transplanted skin graft in an immunologically potent rat model, and studied the mechanism of this protection. We found that systemic or local administration of IgG significantly prolonged the survival of skin grafts with the immune tolerance induced by IgG and subcutaneous local injection of 1mg IgG to adult SD rat yielded the longest survival of skin grafts from 5.8 to 17.3 days. We also found that IgG reduced the number of pro-inflammatory cells especially lymphocytes, neutrophils and basophils, increased the seral levels of anti-inflammatory factors including IL-10 and IL-4, and activated CD4 + CD25 + Foxp3 + regulatory T cells, unveiling the mechanisms of this protective effect. These findings provide new insight to support clinical application of IgG in treating transplantation.

Hypothalamic glucose-sensing neurons regulate the expression of genes encoding feeding-related neuropetides POMC, AgRP, and NPY – the key components governing metabolic homeostasis. AMP-activated protein kinase (AMPK) is postulated to be the molecular mediator relaying glucose signals to regulate the expression of these neuropeptides. Whether other signaling mediator(s) plays a role is not clear. In this study, we investigated the role of ERK1/2 using primary hypothalamic neurons as the model system. The primary neurons were differentiated from hypothalamic progenitor cells. The differentiated neurons possessed the characteristic neuronal cell morphology and expressed neuronal post-mitotic markers as well as leptin-regulated orexigenic POMC and anorexigenic AgRP/NPY genes. Treatment of cells with glucose dose-dependently increased POMC and decreased AgRP/NPY expression with a concurrent suppression of AMPK phosphorylation. In addition, glucose treatment dose-dependently increased the ERK1/2 phosphorylation. Blockade of ERK1/2 activity with its specific inhibitor PD98059 partially (approximately 50%) abolished glucose-induced POMC expression, but had little effect on AgRP/NPY expression. Conversely, blockade of AMPK activity with its specific inhibitor produced a partial (approximately 50%) reversion of low-glucose-suppressed POMC expression, but almost completely blunted the low-glucose-induced AgRP/NPY expression. The results indicate that ERK1/2 mediated POMC but not AgRP/NPY expression. Confirming the in vitro findings, i.c.v. administration of PD98059 in rats similarly attenuated glucose-induced POMC expression in the hypothalamus, but again had little effect on AgRP/NPY expression. The results are indicative of a novel role of ERK1/2 in glucose-regulated POMC expression and offer new mechanistic insights into hypothalamic glucose sensing.

Polymeric micelles with high thermodynamic stability and loading capacity are of tremendous significance for their potential applications in drug delivery. In the present study, super-amphiphiles in the form of poly(ethylene glycol)-crosslinked multi-armed polyethylenimine-g-poly(e-benzyloxycarbonyl-L-lysine)s (PEZ-alt-PEG) were designed, synthesized, and optimized as nanocarriers for hydrophobic drugs. In an aqueous solution, the copolymer PEZ-alt-PEG self-assembled into sub-100-nm spherical shell crosslinked micelles with low toxicity in vitro and in vivo. The crosslinked super-amphiphilic structure of PEZ-alt-PEG could not only enhance the thermodynamic stability of polymeric micelles, but it could also significantly improve the loading capacity of hydrophobic drugs, such as curcumin (CUR). CUR-loaded PEZ-alt-PEG micelles could mediate effective drug delivery with sustained and complete CUR release. The use of PEZ-alt-PEG micellar nanocarriers remarkably improved the cellular uptake of CUR and therefore exhibited effective inhibitory activity on the growth of human hepatoma (HepG2) cells. Compared to free CUR, CUR-loaded polymeric micelles significantly accelerated the apoptosis rate of HepG2 cells. Therefore, PEZ-alt-PEG polymeric micelles, with their high thermodynamic stability, high drug-loading capacity, enhanced drug uptake and improved pharmacodynamic effects, could serve as efficient and promising nanocarriers for poorly water-soluble drugs.

Various reports have indicated that a number of viruses could infect neutrophils, but the multiplication of viruses in neutrophils was abortive. Based on our previous finding that avian influenza viral RNA and proteins were present in the nucleus of infected human neutrophils in vivo, we investigated the possibility of 2009 A (H1N1) influenza viral synthesis in infected neutrophils and possible release of infectious progeny from host cells. In this study we found that human neutrophils in vitro without detectable level of sialic acid expression could be infected by this virus strain. We also show that the infected neutrophils can not only synthesize 2009 A (H1N1) viral mRNA and proteins, but also produce infectious progeny. These findings suggest that infectious progeny of 2009 A (H1N1) influenza virus could be replicated in and released from human neutrophils with possible clinical implications.